scispace - formally typeset
Search or ask a question

Showing papers in "The Journal of Clinical Endocrinology and Metabolism in 1995"


Journal ArticleDOI
TL;DR: A novel mutation in the CYP19 gene in a sister and brother exhibited the cardinal features of the aromatase deficiency syndrome as recently defined and was reported on.
Abstract: The aromatase enzyme complex catalyzes the conversion of androgens to estrogens in a wide variety of tissues, including the ovary, testis, placenta, brain, and adipose tissue. Only a single human gene encoding aromatase P450 (CYP19) has been isolated; tissue-specific regulation is controlled in part by alternative promoters in a tissue-specific manner. We report a novel mutation in the CYP19 gene in a sister and brother. The 28-yr-old XX proband, followed since infancy, exhibited the cardinal features of the aromatase deficiency syndrome as recently defined. She had nonadrenal female pseudohermaphrodism at birth and underwent repair of the external genitalia, including a clitorectomy. At the age of puberty, she developed progressive signs of virilization, pubertal failure with no signs of estrogen action, hypergonadotropic hypogonadism, polycystic ovaries on pelvic sonography, and tall stature. The basal concentrations of plasma testosterone, androstenedione, and 17-hydroxyprogesterone were elevated, wher...

1,395 citations


Journal ArticleDOI
TL;DR: It is suggested that dipeptidyl peptidase-IV is the primary mechanism for GLP-1 degradation in human plasma in vitro and may have a role in inactivating the peptide in vivo.
Abstract: The metabolism of glucagon-like peptide-1 (GLP-1) has not been studied in detail, but it is known to be rapidly cleared from the circulation. Measurement by RIA is hampered by the fact that most antisera are side-viewing or C-terminally directed, and recognize both intact GLP-1 and biologically inactive. N-terminally truncated fragments. Using high pressure liquid chromatography in combination with RIAs, methodology allowing specific determination of both intact GLP-1 and its metabolites was developed. Human plasma was shown to degrade GLP-1-(7-36)amide, forming an N-terminally truncated peptide with a t1/2 of 20.4 +/- 1.4 min at 37 C (n = 6). This was unaffected by EDTA or aprotinin. Inhibitors of dipeptidyl peptidase-IV or low temperature (4 C) completely prevented formation of the metabolite, which was confirmed to be GLP-1-(9-36)amide by mass spectrometry and sequence analysis. High pressure liquid chromatography revealed the concentration of GLP-1-(9-36)amide to be 53.5 +/- 13.7% of the concentration of endogenous intact GLP-1 in the fasted state, which increased to 130.8 +/- 10.0% (P < 0.01; n = 6) 1 h postprandially. Metabolism at the C-terminus was not observed. This study suggests that dipeptidyl peptidase-IV is the primary mechanism for GLP-1 degradation in human plasma in vitro and may have a role in inactivating the peptide in vivo.

820 citations


Journal ArticleDOI
TL;DR: In this article, the effect of vitamin D supplementation on bone turnover and bone loss in elderly women was evaluated by a double-blind, randomized study, and the effect was expressed as the difference in mean (percentage) change between the placebo group and the vitamin D group.
Abstract: The purpose of the study was to determine the effect of vitamin D supplementation on bone turnover and bone loss in elderly women. Three hundred forty-eight women, ages 70 yr and older, were randomized to receive 400 IU vitamin D, ner dav (n = 177) or nlacebo (n = 1711, double-blind, for a period ofi yr. M& outcome measures were bone mineral density of both hips (femoral neck and trochanter) and the distal radius, as well as biochemical markers of bone turnover. The effect of vitamin D supplementation was expressed as the difference in mean (percentage) change between the placebo group and the vitamin D group. The measurements were repeated in 283 women after 1 yr and in 248 women after 2 yr. Vitamin D supplementation significantly increased serum 25hydroxyvitamin D (250HD) (+35 nmol/L) and 1,25dehvdroxwitamin D 11.25-(OHLD1(+7.0 DmolL) levels and urinarv cal&n-&eatinine r&os (+0:5%) and significantly decreasei PTH(l-84) secretion (-0.74 pmol/L) after 1 yr. No effect was found for the parameters of bone turnover. The effect on the bone mineral density of the left femoral neck was + 1.8% in the first yr, +0.2% in the second yr, and + 1.9% during the whole period (95% confidence interval 0.4,3.4%). At the right femoral neck the effects were + 1.5%, + l.l%, and +2.6% (confidence interval 1.1, 4.0%), respectively. No effect was found at the femoral trochanter and the distal radius. Supplementation with 400 IU vitamin D, daily in elderly women slightly decreases PTH secretion and increases bone mineral density at the femoral neck.

473 citations


Journal ArticleDOI
TL;DR: Age, sex, height, BMI, and pubertal maturation were all important factors in determining the circulating levels of IGFBP-3, whereas IGF-I levels were unaffected by BMI.
Abstract: Circulating IGF-I and -II are bound to specific insulin-like growth factor (IGF)-binding proteins (IGFBPs), of which IGFBP-3 binds the majority of the IGFs. IGFBP-3 levels are regulated by GH and have been suggested to provide additional information on GH secretory capacity compared to IGF-I. However, the diagnostic value of IGFBP-3 is still controversial, perhaps because the quality of the available normative data for IGFBP-3 varies. It has recently been shown that a large number of individuals is required to establish reference ranges for IGF-I that take into account age, sex, body mass index (BMI), and pubertal stage. Therefore, we measured IGFBP-3, IGF-I, IGF-II, IGFBP-1, and IGFBP-2 levels by RIA in 907 healthy children to establish well characterized normative data on IGFBP-3 according to age, sex, and pubertal stage and to study the complex relationship between IGFs and their BPs in puberty. We found that IGFBP-3 levels increase with age in children, with maximal levels in puberty; girls experience peak values approximately 1 yr earlier than boys. Age, sex, height, BMI, and pubertal maturation were all important factors in determining the circulating levels of IGFBP-3, whereas IGF-I levels were unaffected by BMI. Comparison of IGFBP-3 with IGF-1 concentrations revealed that they did not exhibit the same developmental pattern in puberty. IGF-I levels increased to relatively higher levels than IGFBP-3, leading to an increasing molar ratio between IGF-I and IGFBP-3 in puberty, when growth velocity is high. Concomitantly, IGF-II and IGFBP-2 levels were unchanged throughout puberty, whereas IGFBP-1 levels declined with age in prepubertal children, with lowest values in puberty. There was a highly significant correlation between IGF-I and -II and IGFBP-3 on a molar basis (r = 0.84; P < 0.0001). Thus, we speculate that IGFBP-3 is pivotal for circulating IGF bioactivity and that the increase in the molar ratio between IGF-I and IGFBP-3 reflects an increase in free, biologically active IGF-I. In conclusion, we have provided normative data on a large group of healthy individuals and conclude that age, sex, height, BMI, and pubertal maturation have to be taken into account before a single IGFBP-3 value in a growth-retarded child can be evaluated properly.

459 citations


Journal ArticleDOI
TL;DR: The CTLA-4 gene or a closely associated gene (including CD28) confers susceptibility to Graves' disease, and this association may be more important in female patients with protective HLA specificities, who otherwise would be at low risk of developing the disease.
Abstract: Graves' disease (GD) is an autoimmune thyroid disease. Multiple genetic factors are believed to be involved in its pathogenesis, but the factors are largely unknown, except for sex (female disease preponderance) and the role of human leukocyte antigen (HLA) genes on chromosome 6. To understand the mechanisms underlying the development of GD, a search for non-HLA-linked genes is crucial, and we tested several candidate genes, including the CTLA-4 gene on chromosome 2q33. CTLA-4 molecules may either facilitate or down-regulate the second signal to T-cells, which is provided by the interaction between the two accessory molecules CD28 and B7. One hundred and thirty-three Caucasian patients (26 males) with GD and 85 local controls were included in this study. Polymerase chain reaction was used to amplify DNA containing the (AT)n repeat within the 3'-untranslated region of exon 3 of the CTLA-4 gene. The 5'-forward primer was radiolabeled, and amplified products were resolved on 5-7% sequencing gels. All subjects were previously typed for HLA class II alleles. Twenty-one alleles were observed with sizes ranging from 88-134 basepairs. In the association analysis, the genotype frequencies between GD patients and controls differed significantly (P = 0.012), and the difference was attributable to a higher frequency of the 106-basepair allele among patients (relative risk, 2.82). When the patients were subdivided with respect to sex and HLA, the phenotype frequencies of allele 106 was higher in the female patients with protective HLA specificities (DQA1*0201 positive/DQA1*0501 negative) than in those with susceptible HLA specificities (DQA1*0201 negative/DQA1*0501 positive; 81.8% vs. 45.5%; P = 0.026). The CTLA-4 gene or a closely associated gene (including CD28) confers susceptibility to GD. This association may be more important in female patients with protective HLA specificities, who otherwise would be at low risk of developing the disease.

454 citations


Journal ArticleDOI
TL;DR: It is concluded that estrogen replacement cannot prevent progressive osteopenia in young women with anorexia nervosa; a subset of patients may have improved BD with estrogen and progestin administration depending on initial body weight; and recovery from anorexa nervosa is associated with significantly improved BD.
Abstract: To study the effects of prolonged anorexia nervosa on bone density (BD) and to determine whether estrogen administration prevents bone loss in women with this disorder, 48 amenorrheic women with anorexia nervosa (mean age, 23.7 yr) were randomized to receive estrogen and progestin replacement (n = 22) or no replacement (n = 26). Clinical variables, biochemical indices, and spinal trabecular BD were measured every 6 months for a mean of 1.5 yr. Initial mean BD (130 +/- 27 mg K2HPO4/cm3, +/- 1 SD) was significantly (P < 0.001) less than normal (176 +/- 26 mg K2HPO4/cm3) and less than 2 SD below normal in 21 of the 48 women. Forty-four women completed the study (19 in the estrogen group and 25 in the control group). The mean duration of follow-up was comparable in the estrogen-treated (1.57 +/- 0.89 yr) vs. the control group (1.41 +/- 0.69 yr). The estrogen-treated group had no significant change in BD compared with the control group; however, there was a 4.0% increase in mean BD in patients with an initial ideal body weight of less than 70% who were treated with estrogen. In contrast, control patients with comparably low initial weight had a 20.1 % decrease in BD. Women in the control group with spontaneous resumption of menses, all of whom had an initial percent ideal body weight of greater than 70%, had a 19.3% increase in bone mass. It is concluded that: 1) estrogen replacement cannot prevent progressive osteopenia in young women with anorexia nervosa; 2) a subset of patients may have improved BD with estrogen and progestin administration depending on initial body weight; and 3) recovery from anorexia nervosa is associated with significantly improved BD.

433 citations


Journal ArticleDOI
Jan Holte1, T. Bergh1, Christian Berne1, Leif Wide1, Hans Lithell1 
TL;DR: Insulin resistance in obese women with PCOS was reduced by weight loss to similar levels as BMI-matched control subjects, suggesting that insulin resistance in PCOS is not a feature of PCOS per se.
Abstract: The impact of weight reduction on metabolic, endocrine, and anthropometric variables was studied in 13 obese, insulin-resistant women with the polycystic ovary syndrome (PCOS). Insulin sensitivity (euglycemic insulin clamp), insulin secretion and glucose tolerance (iv glucose tolerance test), basal sex steroid hormones, gonadotropins and free fatty acids (FFA), skin folds and waist hip ratio (WHR) were evaluated before (PCO-BD) and after (PCO-AD) diet-induced weight reduction to a weight stable level [mean (SD) diet duration 14.9 (6.2) months]. Mean weight loss was 12.4 kg (4.7; P < 0.0001), equalling a reduction from a body mass index (BMI) of 32.2 (3.7) kg/m2 to 27.6 (3.7; P < 0.0001) kg/m2. The results were compared with those of two groups of weight stable (no diet) women, 21 with PCOS (PCO-ND) and 23 normal control subjects (C), who were matched to the BMI the diet group reached after weight loss. Insulin sensitivity index (M/I) improved on average 132% (P < 0.001) and plasma FFA by 32% (P < 0.01), serum sex hormone binding globulin levels increased by 35% (P < 0.01), and the sum of truncal-abdominal skin-folds (subscapular, umbilical, and suprailiacal) were reduced by 28% (P < 0.0001), whereas the early insulin response to iv glucose, the levels of gonadotropins and androstenedione, and the femoral sc fat did not change significantly with weight loss. M/I, levels of SHBG and FFA and truncal-abdominal fat reached levels similar to the controls, whereas PCO-ND had lower M/I (P < 0.01) and SHBG levels (P < 0.0001), greater concentrations of FFA (P < 0.01) and truncal-abdominal fat (P < 0.05) than C. Among women with normal glucose tolerance, the insulin increment was higher in both PCO-AD (P < 0.05) and PCO-ND (P < 0.01) than in C. There was a strong correlation between M/I and sum of truncal-abdominal skinfolds in all groups (PCO-BD: r = 0.82; P < 0.001, PCO-AD: r = 0.68; P < 0.05, PCO-ND: r = 0.81; P < 0.0001, C: r = 0.44; P < 0.05). The variation in M/I in PCO-AD and PCO-ND (pooled) was best explained by FFA and truncal-adbominal fat (model R2 = 0.67). In conclusion, insulin resistance in obese women with PCOS was reduced by weight loss to similar levels as BMI-matched control subjects, suggesting that insulin resistance in PCOS is not a feature of PCOS per se.(ABSTRACT TRUNCATED AT 400 WORDS)

399 citations


Journal ArticleDOI
TL;DR: The OXT neurons of the PVN seem to be good candidates for playing a physiological role in ingestive behavior as "satiety neurons" in the human hypothalamus.
Abstract: Animal experiments have shown that the parvocellular oxytocin (OXT) neurons of the hypothalamic paraventricular nucleus (PVN) inhibit food intake. In the present study, the PVN and its OXT neurons have been investigated in an extreme human eating disorder, i.e. the Prader-Willi syndrome (PWS). PWS patients are characterized by gross obesity, insatiable hunger, hypotonia, hypogonadism, and mental retardation. The PVN of 5 PWS patients (2 males and 3 females), varying in age between 22-64 yr, and 27 controls (14 males and 13 females) without any primary neurological or psychiatric diseases was morphometrically investigated after conventional staining with thionine and immunocytochemical staining for OXT and vasopressin (AVP). The thionine-stained volume of the PVN was 28% smaller in PWS patients (P = 0.028), and the total cell number was 38% lower (P = 0.009). The immunoreactivity for OXT and AVP was decreased in PWS patients, although the variability within the groups was high. A strong and highly significant decrease (42%; P = 0.016) was found in the number of OXT-expressing neurons of the PWS patients. The volume of the PVN-containing OXT-expressing neurons decreased by 54% (P = 0.028) in PWS. The number of AVP-expressing neurons in the PVN did not change significantly. The OXT neurons of the PVN seem to be good candidates for playing a physiological role in ingestive behavior as "satiety neurons" in the human hypothalamus.

387 citations


Journal ArticleDOI
TL;DR: The 24-h mean plasma concentration of total testosterone (T) was measured in 33 healthy, regularly cycling, nonobese women between 21 and 51 yr of age and found that the concentration showed a steep decline with age; the regression equation was T (nanomoles per L) = 37.8 x age-1.12.
Abstract: The 24-h mean plasma concentration of total testosterone (T) was measured in 33 healthy, regularly cycling, nonobese women between 21 and 51 yr of age. Percent free T was measured in 17 of them. Plasma dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) were measured in 24 of them, and the DHEA-to-T and DHEAS-to-T ratios were calculated. It was found that the concentration of total T showed a steep decline with age; the regression equation was: T (nanomoles per L) = 37.8 x age-1.12 (r = -0.54; P < 0.003). According to this equation, the expected T concentration of a woman of 40 would be 0.61 nmol/L, about half that of a woman of 21 (1.3 nmol/L). The percent free T did not vary significantly with age, so free T concentration likewise showed a steep decline with age. The DHEA-to-T and DHEAS-to-T ratios were both age invariant, clearly because the levels of DHEA and DHEAS also decline steeply with age, as previously reported.

386 citations


Journal ArticleDOI
TL;DR: The goals of the current study were to examine the IGF system in FCS from term fetuses with normal growth, those with intrauterine growth retardation (IUGR), and those who were large for gestational age (LGA) and in F CS from normal weight preterm andTerm fetuses in the neonatal period from the day of birth until 7 days of age.
Abstract: Insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs), and insulin are believed to be important in the regulation of fetal and neonatal growth. We previously reported that the profiles of IGFBPs in fetal cord serum (FCS) were dependent on the growth/metabolic status of the fetus. The goals of the current study were to examine the IGF system in FCS from term fetuses with normal growth, those with intrauterine growth retardation (IUGR), and those who were large for gestational age (LGA) and in FCS from normal weight preterm (25-37 weeks) and term fetuses in the neonatal period from the day of birth (day 0) until 7 days of age (day 7). Western ligand blotting (WLB) of term FCS revealed IGFBPs with mol wt of 43 and 38 kilodaltons (kDa; IGFBP-3), 34 kDa (IGFBP-2), 28 kDa (IGFBP-1 and glycosylated IGFBP-4), and 24 kDa (IGFBP-4). In IUGR FCS, there was a 50% decrease in IGFBP-3 detected by WLB, which was shown not to be due to an IGFBP-3 protease in IUGR sera. In LGA FCS, IGFBP-3 levels were elevated 2-fold by densitometric analysis of ligand blots. In normal term FCS, the following levels (+/- SE) were present: IGF-I, 76 +/- 16; IGF-II, 401 +/- 38; IGFBP-3, 700 +/- 112; IGFBP-1, 77 +/- 10 ng/mL; and insulin, 3.8 +/- 1.6 microU/mL. In IUGR FCS, IGF-I, IGF-II, and IGFBP-3 were significantly reduced, and IGFBP-1 was 7-fold higher than in FCS from normal weight fetuses. In LGA FCS, IGF-I, insulin, and IGFBP-3 were significantly increased, whereas IGFBP-1 was significantly decreased. During the neonatal period, IGF-I levels on day 0 were 4-fold higher in FCS from term (38-40 weeks) compared to preterm (25-31 weeks) newborns. FCS IGF-II levels did not change significantly on day 0 between 25-40 weeks gestation. In the first 7 days of postnatal life, IGF-I levels were unchanged in preterm newborns, whereas in term neonates, IGF-I levels decreased precipitously on day 1, remained low during the first 3 days of life, and returned to birth levels by the end of the first week. In contrast, IGF-II and IGFBP-3 levels did not significantly change during the first week of life in preterm or term newborns.(ABSTRACT TRUNCATED AT 400 WORDS)

385 citations


Journal ArticleDOI
TL;DR: A chemiluminescence-based GH assay with 30- to 100-fold increased sensitivity and high sensitivity and specificity and deconvolution analysis was used to quantitate basal and pulsatile GH secretion from 24-h serum GH concentration profiles in 26 healthy lean and obese men.
Abstract: A chemiluminescence-based GH assay with 30- to loo-fold increased sensitivity recently disclosed combined basal and pulsatile GH secretion in men. However, how age, sex steroid hormones, and obesity singly and jointly influence the basal us. pulsatile modes of GH release is not known. We used the foregoing assay (detection threshold, 0.002-0.005 pg/L) and high sensitivity and specificity (290% each) deconvolution analysis to quantitate basal and pulsatile GH secretion from 24-h serum GH concentration profiles in 26 healthy lean and obese men, whose ages spanned 18-63 yr and whose percentage body fat ranged from 12-47%. Concentrations of serum insulin-like growth factor I (IGF-I), IGF-I-binding protein-l (IGFBP-l), and IGFBP-3 were related to specific measures of basal or pulsatile GH release. We observed that mean (24-h) serum GH concentrations embraced a 140-fold range from 0.013-1.8 pg/L and were related negatively to age (r = -0.50; P < O.Ol), percentage body fat (r = -0.620; P < 0.011, and their interaction (r = -0.610; P < 0.01). In contrast, testosterone was a robustly positive statistical determinant of mean serum GH values (r = 0.628; P = 0.0006). Stepwise multivariate regression analysis disclosed that percentage body fat alone and jointly with the serum testosterone concentration controlled, respectively, 38% and 50% of the total variability in GH levels (P = 0.0013 and P = 0.0008). As assessed by deconvolution analysis, GH secretory burst mass was negatively related to percentage body fat (r = -0.621; P < 0.01) and positively to serum testosterone (r = 0.529; P = 0.0054). The calculated half-life of GH correlated positively with serum estradiol (r = 0.447; P = 0.0321, and negatively with percentage body fat (r = -0.437; P = 0.048). Basal GH secretion rates were negatively related to serum estradiol (r = -0.485; P = 0.016). In contrast, GH secretory burst frequency and duration were unrelated to age, percentage body fat, or sex steroids. The fraction of total GH secreted in bursts was negatively correlated with the body mass index (r = - 0.540; P < 0.01). Serum IGF-I concentrations were positively related to total pulsatile GH secretion (r = 0.690; P = 0.0011) and negatively to age (r = -0.597; P = 0.007) and percentage body fat (r = -0.611; P = 0.009). Serum IGFBP-3 was inversely proportional to the basal GH secretion rate (r = -0.467; P = 0.044). In contrast, IGFBP-1 concentrations correlated positively with GH secretory burst mass (r = 0.674; P = 0.0016) as well as basal GH secretion (r = 0.519; P = 0.023), and negatively with age, and percentage body fat and their interactions (absolute r values = 0.517-0.653; P 5 0.021). The serial orderliness of GH release, as assessed by a novel approximate entropy (ApEn) statistic, revealed decreased orderliness (higher ApEn) of GH release with increasing age (r = 0.482; P = 0.019) and adiposity (r = 0.505;

Journal ArticleDOI
TL;DR: The aim of this research is to provide a clear picture of the unique needs of children in the developing world and to help policymakers and clinicians better understand these needs.
Abstract: Department of Pediatrics (R.G.R., S.L., L.L.), Oregon Health Sciences University, Portland, Oregon 97201; the Department of Pediatrics, University of Gothenburg (K,A. W.), Gothenburg, Sweden; the Department of Pediatrics, University of Chile (F.C.), Santiago, Chile; Department of Pediatrics, University of California (Olive View Medical Center) (S.D.F.), Sylmar, California 91342; Department of Pediatrics, UCLA (B.L.), Los Angles, California 90024; Tokyo Metropolitan Kiyose Children’s Hospital (Y.H.), Tokyo, Japan; the Department of Pediatrics, Stanford University (R.L.H.), Stanford, California 94305; the Department of Medicine, Cedars Sinai Medical Center (S.M.), Los Angeles, California 90048; the Department of Pediatrics, Institute of Child Health (M.A.P.), London, United Kingdom; the Department of Pediatrics, Universitat Tubingen (M.B.R.), Tubingen, Germany; the Department of Pediatrics, Baystate Medical Center (E.O.R.), Springfield, Massachusetts 01199; the Department of Pediatrics, University of Virginia Health Sciences Center (A.D.R.), Charlottesville, Virginia 22908; the Department of Pediatrics, University of North Carolina (L.E. U.), Chapel Hill, North Carolina 27599; and Royal Childrenjs Hospital (G.A. W.), Melbourne, Australia

Journal ArticleDOI
TL;DR: Results indicate that stress-responsive neurohormonal systems are restrained in lactating women, as measured by plasma ACTH, cortisol, and glucose responses to exercise.
Abstract: In the rat, lactation suppresses a variety of physiological responses to stress. We investigated whether stress-responsive neurohormonal systems are also restrained during breast feeding in humans. We chose treadmill exercise as a stressor because this stimulus produces an exercise intensity-dependent activation of the hypothalamic-pituitary-adrenal axis and the sympathomedullary system that is independent of differences in physical conditioning among subjects. Ten lactating and ten nonlactating women who were between 7 and 18 weeks postpartum performed 20 min of graded treadmill exercise. The final 5 min of exercise was set to elicit 90% of the maximal oxygen uptake of each subject. Plasma ACTH, cortisol, and glucose responses to exercise were significantly attenuated in lactating women (P < 0.001, P < 0.05, and P < 0.001, respectively). Basal norepinephrine levels were also reduced in lactating women (P < 0.05). These results indicate that stress-responsive neurohormonal systems are restrained in lactating women.

Journal ArticleDOI
TL;DR: It is demonstrated that transsphenoidal surgery is a safe and effective treatment for patients with Cushing's disease, however, after successful surgery there is a steady increase in the percentage of recurrences, which continues with time.
Abstract: Hypercortisolism attributable to hypersecretion of ACTH by a pituitary adenoma is an uncommon and progressively lethal disease. Because of its rarity, it has been difficult to collect a large series of patients in order to identify the prognostic factors influencing the outcome after transsphenoidal surgery. We conducted a multicenter, retrospective analysis of the early and late results of surgical treatment of Cushing's disease. Files of patients with Cushing's disease who underwent transsphenoidal surgery between 1975 and 1990 were collected from 25 institutions throughout Europe. Data from 668 of 716 patients were suitable for statistical analyses. Surgical mortality was 1.9%, and major morbidity occurred in 97 patients (14.5%). Clinical and biochemical remission of Cushing's disease after surgery occurred in 510 cases (76.3%). Identification of the tumor by neuroradiological imaging or at operation with histopathological corroboration was associated with remission of hypercortisolism. Recurrence of the disease occurred in 65 (12.7%) of 510 patients in remission after surgery at a mean time of 39.3 months (range 6-104 months). The distribution of the recurrences did not show any apparent plateau or cluster throughout the follow-up period. Low postoperative steroid levels, absence of cortisol response to CRH, and the need for long-term glucocorticoid substitution therapy were all associated with a high probability of long-term remission. Our study demonstrates that transsphenoidal surgery is a safe and effective treatment for patients with Cushing's disease. However, after successful surgery there is a steady increase in the percentage of recurrences, which continues with time. Patients who after operation had hypoadrenocorticism and needed long-term glucocorticoid substitution therapy had the lowest risk of relapse.

Journal ArticleDOI
TL;DR: It is concluded that lymphocytic hypophysitis should be considered in the differential diagnosis of females with pituitary enlargement presenting in the peripartum period as well as those patients in whompituitary hormone deficiency and/or excess is noted in association with a co-existing autoimmune disorder.
Abstract: This report describes the clinicopathological features of 16 patients with lymphocytic hypophysitis and compares the results with the published literature. There were 2 males and 14 females in this series. In 10 of the 14 females (71%), the presentation was associated with pregnancy. Nine patients (56%) presented with symptoms of an expanding pituitary sellar mass, 10 (63%) had anterior pituitary hypofunction, 3 had diabetes insipidus (19%). Progressive undiagnosed hypopituitarism led to the demise of 3 patients (19%). Hyperprolactinemia was encountered in 6 patients (38%), and elevated growth hormone levels (GH) resulted in IGF-1 excess in one patient. Computed tomography (CT) and magnetic resonance (MR) imaging revealed features of a pituitary mass mimicking an adenoma in 10 cases (83%). Four patients (25%) had associated autoimmune thyroiditis. Morphologic examination of the pituitary and immunohistochemistry showed a polyclonal lymphoplasmacytic infiltrate as well as occasional neutrophils, eosinophil...

Journal ArticleDOI
TL;DR: An increase in serum FSH and decreases in E2 and INH are the major endocrine changes associated cross-sectionally with the menopausal transition.
Abstract: In a study of the endocrinology of the perimenopausal years, levels of serum FSH, estradiol (E2), immunoreactive inhibin (INH), testosterone, and sex hormone-binding globulin were measured in a population-based sample of 380 women (mean age, 49.4 yr; range, 45.6-56.9 yr). Subjects were divided into women who reported continuing regular menstrual cycles (27%; group I), a change in menstrual flow without a change in frequency (23%; group II), a change in frequency but no change in flow (9%; group III), changes in both frequency and flow (28%; group IV), and at least 3 months since their last menstrual period (13%; group V). After adjusting for age and body mass index, the geometric mean FSH increased across menstrual groups and, compared with group I, was 53% higher in group IV (P < 0.0005) and 253% higher in group V (P < 0.0001). Age- and body mass index-adjusted geometric means for E2 and INH in group V were 54% and 53% of those in group 1, respectively (P < 0.005, P < 0.0001). Women in group V who did not have a menstrual period in the next year had higher FSH and lower E2 and INH levels than those who subsequently went on to have at least one more menstrual period (P < 0.05). FSH was negatively correlated with E2 (r = -0.30) and INH (r = -0.39), whereas INH was positively correlated with E2 (r = 0.45). We conclude that an increase in serum FSH and decreases in E2 and INH are the major endocrine changes associated cross-sectionally with the menopausal transition.

Journal ArticleDOI
TL;DR: It is indicated that protein or energy restriction in children leads to changes in IGF-I or specific IGFBPs, and measurement of IGFBP-2 may be useful in monitoring the response to refeeding in children who have been ingesting suboptimal amounts of protein.
Abstract: Serum concentrations of insulin-like growth factor-I (IGF-I) and IGF-binding protein-1 (IGFBP-1), -2, and -3 are influenced by dietary intake in normal adults. These studies were undertaken to determine the influence of dietary factors on these proteins in children and to compare the responses in children to those in adults. Eight adults and eight pubertal children underwent energy restriction (50% reduction intake) for 6 days and were refed a normal diet for an additional 6 days. Basal energy intakes during the prerestriction periods were 70 Cal/kg in children and 35 Cal/kg in adults. A second group of 8 adults and 6 children underwent protein restriction (decreased from 1.0 to 0.66 g/kg in both groups) for 6 days and were refed a normal diet for 6 days. Calorie restriction resulted in a significant decrease in nitrogen balance in adults and children. Likewise, IGF-I concentrations declined significantly in both adults and children. In contrast, IGFBP-1 concentrations were significantly increased in adults (from 40 +/- 6 to 62 +/- 4 ng/mL; P < 0.05), but not in children. Serum concentrations of IGFBP-2 did not change in either group in response to energy restriction. IGFBP-3 declined significantly in the children (3189 +/- 90 to 2843 +/- 96 ng/mL; P < 0.05), but not in the adults. Protein restriction also caused negative nitrogen balance in both children and adults and a decline in the mean IGF-I concentration in the adults. IGFBP-2 concentrations rose significantly in both adults (131 +/- 15 to 164 +/- 15 ng/mL; P < 0.005) and children (126 +/- 13 to 158 +/- 15 ng/mL; P < 0.05) in response to protein restriction and returned to normal during refeeding. IGFBP-3 was slightly, but significantly, reduced in response to protein restriction in adults (3518 +/- 180 to 3328 +/- 151 ng/mL; P < 0.05), but not children. The findings indicate that protein or energy restriction in children leads to changes in IGF-I or specific IGFBPs. Changes in IGFBP-2 are sensitive to protein restriction, and measurement of IGFBP-2 may be useful in monitoring the response to refeeding in children who have been ingesting suboptimal amounts of protein.

Journal ArticleDOI
TL;DR: The therapeutic effectiveness of 131I treatment in patients with elevated Tg and negative diagnostic whole body scans is indicated by the conversion to negative RxWBS, the statistically significant decrease in the mean Tg level, and the reduction of serum Tg to 5 ng/mL or less in 50% of patients.
Abstract: Seventeen patients with papillary thyroid cancer whose serum thyroglobulin (Tg) levels were elevated when hypothyroid, but whose diagnostic whole body scans were negative, were treated with 150-300 mCi 131I. All patients had total thyroidectomy and 131I ablation for thyroid remnants. Before the study, 9 patients had 131I therapy for tumor recurrence and/or metastases, and 5 patients had excisions of nonfunctioning metastasis. Radiological studies did not reveal evidence of metastases. In the initial evaluation, Tg levels ranged from 8-480 ng/mL (24 pmol/L to 1.5 nmol/L), and posttherapy whole body scans (RxWBS) revealed undiagnosed local recurrence and/or metastases in 16 of 17 patients. Follow-up from 6 months to 5 yr is available in 16 patients. RxWBS after a second treatment was positive in 8 of 13 patients, and after a third treatment in 5 of 5 patients, although in 3 cases, uptake in distant metastasis had disappeared. In 8 patients, Tg fell to 5 ng/mL or less. In 1 patient, RxWBS became negative, but Tg remained elevated; subsequent treatment revealed local and mediastinal uptake, but previous lung uptake had disappeared. In 8 patients, RxWBS remains positive, and elevated Tg persists. A total of 35 RxWBS were performed; 29 were positive. Follow-up Tg concentrations decreased in 81% of patients after the first treatment, in 90% after the second treatment, and in 100% of the patients after the third treatment. Tg (mean +/- SE) decreased from 74 +/- 33 ng/mL in the first evaluation to 62 +/- 32 ng/mL in the second study and 32 +/- 20 ng/mL in the third study. The therapeutic effectiveness of 131I treatment in patients with elevated Tg and negative diagnostic whole body scans is indicated by the conversion to negative RxWBS, the statistically significant decrease in the mean Tg level, and the reduction of serum Tg to 5 ng/mL or less in 50% of patients. Further experience with this therapeutic approach is required to evaluate its effectiveness in improving prognosis and survival.

Journal ArticleDOI
TL;DR: It was concluded that the turnover rate of depot triglycerides is more rapid in abdominal compared to femoral sc adipose tissue in men and T supplementation inhibits triglyceride uptake and LPL activity and causes a more rapid turnover of triglycerides only in the sc abdominal adipose tissues region.
Abstract: Studies on regional differences of adipose tissue metabolism have mainly been performed in vitro. To allow measurements of lipid uptake in vivo in man, radioactive label from [9,10-3H]oleic acid in 80 g orally administered milk fat was measured after 4 h in abdominal and femoral sc adipose tissues in 28 middle-aged, abdominally obese men. Radioactivity was measured in adipose tissue triglycerides extracted from needle biopsies. Lipoprotein lipase (LPL) activity was also measured. Uptake of label in triglycerides and LPL activity were higher (20% and 15%, respectively; P < 0.05) in the abdominal compared to the femoral adipose tissue region. The men were then randomly assigned to three groups, receiving testosterone (T), dihydrotestosterone, or placebo, for 9 months. After 2 months of treatment, the procedure of administration of label was repeated, this time using [U-14C]oleic acid as a marker. Measurements of radioactive label was then performed after 4 h and monthly up to 7 months. Supplementation with ...

Journal ArticleDOI
TL;DR: It is demonstrated that the 10 most common mutations observed in the 21-hydroxylase gene result in phenotypes that are not always concordant with the genotype, even within families.
Abstract: Steroid 21-hydroxylase deficiency is the most frequent cause of congenital adrenal hyperplasia. We have determined the 21-hydroxylase genotype in 197 patients with congenital adrenal hyperplasia owing to 21-hydroxylase deficiency and assessed phenotypic characteristics based on 1) genital status with respect to virilization in females, 2) ACTH stimulation tests to evaluate the secretion of androgens and 17-hydroxyprogesterone, and 3) salt deprivation tests to precisely describe the phenotype with respect to aldosterone deficiency and salt wasting. After dividing our patients into 26 21-hydroxylase gene mutation-identical groups, we found that, in general, the patient's phenotype matched the severity of the genotype. However, in 13 of these groups, the genotype did not always predict the phenotype, even within families. This study, has demonstrated that the 10 most common mutations observed in the 21-hydroxylase gene result in phenotypes that are not always concordant with the genotype.

Journal ArticleDOI
TL;DR: It is inferred that carbenoxolone, by inhibiting hepatic 11 beta-reductase and reducing intrahepatic cortisol concentration, increases hepatic insulin sensitivity and decreases glucose production, and plasma cortisone provides an inactive pool that can be converted to active glucocorticoids at sites where 11 Beta-Reductase is expressed.
Abstract: In the kidney, conversion of cortisol to cortisone by the enzyme 11 beta-hydroxysteroid dehydrogenase protects mineralocorticoid receptors from cortisol. In the liver, a different isoform of the enzyme favors 11 beta-reductase conversion of cortisone to cortisol. We have tested the hypothesis that hepatic 11 beta-reductase enhances glucocorticoid receptor activation in the liver by inhibiting the enzyme with carbenoxolone and observing effects on insulin sensitivity. Seven healthy males took part in a double blind randomized cross-over study in which oral carbenoxolone (100 mg every 8 h) or placebo was administered for 7 days. Euglycemic hyperinsulinemic clamp studies were then performed, including measurement of forearm glucose uptake. Carbenoxolone increased whole body insulin sensitivity (M values for dextrose infusion rates, 41.1 +/- 2.4 mumol/kg.min for placebo vs. 44.6 +/- 2.3 for carbenoxolone; P < 0.03), but had no effect on forearm insulin sensitivity. We infer that carbenoxolone, by inhibiting h...

Journal ArticleDOI
TL;DR: Observations suggest that breast cancer cells can adapt to low levels of estrogens by enhancing their sensitivity to E2, as a result of adaptation to low E2 levels.
Abstract: Genetic and environmental factors can modulate the level of sensitivity to various hormones, including estrogens. Enhanced sensitivity to estradiol (E2) has been demonstrated in several biological conditions, such as in sheep during the nonbreeding season, in untreated patients with Turner's syndrome, and in the prepubertal state in normal girls. We postulated that secondary responses to hormonal therapy in patients with breast cancer could also result from enhanced E2 sensitivity, developing as an adaptive mechanism to E2 deprivation. The present study used the MCF-7 human breast cancer cell line as a model system to test the concept that enhanced sensitivity to E2 may occur as a result of adaptation to low E2 levels. After depriving MCF-7 cells of estrogens in tissue culture medium for periods of 1-6 months, we established conditions under which replication could be stimulated maximally by 10(-14)-10(-15) mol/L E2. In contrast, wild-type cells not exposed to estrogen deprivation required 10(-10) mol/L E...

Journal ArticleDOI
TL;DR: Compared to women with the bb variants, women with BB allelic variants of the VDR have reduced calcium absorption efficiency on low calcium intake, consistent with a functional defect in the intestinal VDR.
Abstract: The finding that the link between polymorphism at the vitamin D receptor (VDR) gene and rates of bone loss from the femoral neck in postmenopausal women is enhanced at low calcium intakes suggests that intestinal calcium absorption is a site of differential action of the VDR alleles. 1,25-Dihydroxyvitamin D [1,25-(OH)2D] and its receptor mediate active calcium transport, the major mechanism of calcium absorption at low calcium intakes. We compared fractional calcium absorption in healthy late postmenopausal women with (bb) and without (BB) the BSM-1 restriction site. In 60 women (26 BB and 34 bb), we measured calcium absorption and plasma 1,25-(OH)2D after 2 weeks on a high (1500 mg/day) and 2 weeks on a low (< 300 mg/day) calcium intake. The mean 45Ca absorption indexes were similar in the two groups on the high calcium intake [19.01 +/- 1.12% (+/- SEM)/L in BB and 20.45 +/- 0.97%/L in bb; P = 0.346] and differed significantly on the low calcium intake (20.57 +/- 1.10%/L vs. 23.66 +/- 0.95%/L; P = 0.044). Calcium restriction induced similar percent increases in plasma 1,25-(OH)2D, but the BB group had a smaller increase in the fractional 45Ca absorption index [7.8 +/- 3.8% (+/- SEM) vs. 20.7 +/- 3.3% in bb; P = 0.016; increments adjusted for initial absorption value]. In conclusion, compared to women with the bb variants, women with BB allelic variants of the VDR have reduced calcium absorption efficiency on low calcium intake, consistent with a functional defect in the intestinal VDR. The impact of this heritable difference is reduced at higher calcium intakes.

Journal ArticleDOI
TL;DR: The results suggest that the effects of hCG on the development and course of OHSS may be mediated by the production of VEGF/VPF by GCs, which is dose and time dependently enhanced by hCG in vitro.
Abstract: Ovarian hyperstimulation syndrome (OHSS) is a severe complication arising from controlled ovarian stimulation treatment. This iatrogenic condition is potentially lethal and occurs in 0.3-5% of stimulated ovarian cycles. hCG exacerbates OHSS. The pathophysiology of OHSS is still unknown; therefore, treatment regimens are aimed at ameliorating symptoms. Prominent features of OHSS are an elevated risk of thromboembolism due to enhanced production of von Willebrand factor by endothelial cells and ascites, or pulmonary edema due to increased vascular permeability followed by third space fluid accumulation. Both of these sequelae can be evoked by vascular endothelial growth factor (VEGF), also known as vascular permeability factor (VPF). High concentrations of VEGF/VPF have been demonstrated in ascitic fluid from patients with OHSS, but the source of VEGF/VPF in these patients remained unidentified. Here we report that the messenger ribonucleic acid expression of VEGF/VPF in human luteinized granulosa cells (GCs) is dose and time dependently enhanced by hCG in vitro. Furthermore, VEGF/VPF proteins are produced by GCs. Our results suggest that the effects of hCG on the development and course of OHSS may be mediated by the production of VEGF/VPF by GCs.

Journal ArticleDOI
TL;DR: A 4-week, soy-supplemented diet was expected to have estrogenic effects on the liver and pituitary in postmenopausal women, but estrogeniceffects were not seen, and at most, there was a small estrogenic effect on vaginal cytology.
Abstract: We tested the hypothesis that postmenopausal women on a soy-supplemented diet show estrogenic responses. Ninety-seven postmenopausal women were randomized to either a group that was provided with soy foods for 4 weeks or a control group that was instructed to eat as usual. Changes in urinary isoflavone concentrations served as a measure of compliance and phytoestrogen dose. Changes in serum FSH, LH, sex hormone binding globulin, and vaginal cytology were measured to assess estrogenic response. The percentage of vaginal superficial cells (indicative of estrogenicity) increased for 19% of those eating the diet compared with 8% of controls (P = 0.06 when tested by ordinal logistic regression). FSH and LH did not decrease significantly with dietary supplementation as hypothesized, nor did sex hormone binding globulin increase. Little change occurred in endogenous estradiol concentration or body weight during the diet. Women with large increases in urinary isoflavone concentrations were not more likely to show...

Journal ArticleDOI
TL;DR: In man, the reported association of a small fetus and a large placenta predisposing to adult hypertension cannot be explained on the basis of defective 11 beta HSD activity, and the placentA offers an immense reservoir for F clearance and may be a principal factor driving fetal ACTH secretion and, hence, fetal adrenal steroidogenesis.
Abstract: Two isoforms of 11 beta-hydroxysteroid dehydrogenase (11 beta HSD) have been described which catalyze the interconversion of cortisol (F) to cortisone (E). 11 beta HSD activity has previously been reported in placenta and fetal membranes, where its role may be to protect the developing fetus from glucocorticoid excess. Furthermore, in the rat, an association between placental 11 beta HSD activity and the subsequent development of hypertension in the offspring has been reported. We have characterized the isoforms of 11 beta HSD in human fetal membranes and dissected placental tissue at term and investigated the relationship between placental 11 beta HSD activity and fetal and placental weights. 11 beta HSD activity studies in the presence of 0.1 mumol/L F and NAD (indicative of type 2 isoform activity) revealed high levels of activity in trophoblast dissected free of vessels (561 +/- 87 pmol E/h.mg protein; n = 4) > undissected placenta > cotyledenous vessels dissected away from trophoblast > placental and reflected amnion. In contrast, in the presence of 2.5 mumol/L F and NADP (indicative of type 1 isoform activity), only decidua and chorion demonstrated significant levels of 11 beta HSD activity. Type 1 11 beta HSD activity in chorion was probably due to decidual contamination, in that it was absent in decidua-free fused chorion obtained from a twin pregnancy. In keeping with these data, type 1 11 beta HSD messenger ribonucleic acid (1.5 kilobases) was detected in decidua, but in no other tissue, and high levels of type 2 11 beta HSD messenger ribonucleic acid (1.9 kilobases) were found in undissected placenta and trophoblast. In 27 term placentas, 11 beta HSD activity varied from 194-448 pmol E/h.mg protein. There was a weak, but significant, positive correlation between term placental 11 beta HSD activity and fetal weight (r = 0.408; P = 0.034), but no correlation with placental weight. Thus, in man, the reported association of a small fetus and a large placenta predisposing to adult hypertension cannot be explained on the basis of defective 11 beta HSD activity. However, the placenta offers an immense reservoir for F clearance (1.73-7.95 mumol/min.placenta) and may be a principal factor driving fetal ACTH secretion and, hence, fetal adrenal steroidogenesis.

Journal ArticleDOI
TL;DR: It is confirmed that weight loss induced by a low calorie diet is effective in improving hyperinsulinemia and hyperandrogenism in obese and hirsute women.
Abstract: Evidence suggests that hyperinsulinemic insulin resistance may increase serum levels of ovarian androgens and reduce sex hormone-binding globulin (SHBG) levels in humans. The present study was conducted to assess the effect of administration of the biguanide metformin, a drug commonly used in the treatment of diabetes mellitus, on androgen and insulin levels in 24 hirsute patients. The patients selected for the study were obese, with a body mass index higher than 25 kg/m2 and high fasting insulin (> 90 pmol/L) and low SHBG levels (< 30 nmol/L). All patients were given a low calorie diet (1500 Cal/day) and randomized for either metformin administration at a dose of 850 mg or a placebo, twice daily for 4 months, in a double blind study. In the placebo group, diet resulted in a significant decrease in body mass index (30.8 +/- 1.0 vs. 32.7 +/- 1.5 kg/m2; P < 0.0001), fasting insulin (127 +/- 11 vs. 156 +/- 14 pmol/L; P < 0.01), non-SHBG-bound testosterone (0.19 +/- 0.02 vs. 0.28 +/- 0.03 nmol/L; P < 0.02), androstenedione (5.8 +/- 0.5 vs. 9.0 +/- 1.1 nmol/L; P < 0.03), and 3 alpha-diolglucuronide (8.6 +/- 1.1 vs. 11.7 +/- 1.9; P < 0.005) plasma concentrations and a significant increase in the glucose/insulin ratio (0.047 +/- 0.005 vs. 0.035 +/- 0.003; P < 0.001) and plasma concentrations of SHBG (26.0 +/- 3.3 vs. 19.1 +/- 1.9 nmol/L; P < 0.001) and dehydroepiandrosterone sulfate (8.7 +/- 1.5 vs. 8.4 +/- 1.3; P < 0.05). Beneficial effects of diet were not significantly different in the patients who were given metformin instead of placebo. These results confirm that weight loss induced by a low calorie diet is effective in improving hyperinsulinemia and hyperandrogenism in obese and hirsute women. With our study design, metformin administration had no additional benefit over the effect of diet.

Journal ArticleDOI
TL;DR: The data demonstrate that GH, which is known to have multiple somatic effects, produces an improvement in the quality of life of adults with GHD.
Abstract: We examined the effect of GH supplementation on the psychological capacity and sense of well-being in 36 patients with adult-onset GH deficiency (GHD). Recombinant human GH was given in a 21-month cross-over, double blind trial, and quality of life was assessed by using three self-rating questionnaires: the Hopkins Symptom Check List (HSCL), the Nottingham Health Profile (NHP), and the Psychological General Well-Being index. In addition, at the final examination the spouses completed a short questionnaire concerning their partner. Before treatment, the patients had lowered quality of life as determined by the HSCL and NHP inventories, and a correlation between the duration of GHD and the reported symptoms was observed. Upon treatment, the HSCL score was lower (better) after placebo administration (mean +/- SD, 84 +/- 21.3) than at baseline (89 +/- 18.9; P = NS) and fell to 80.2 +/- 18.5 (P < 0.001) when active drug was given. The subscales regarding anxiety, fearfulness, and cognition were the most sensit...

Journal ArticleDOI
TL;DR: It is concluded that fatty acids as well as ketone bodies diminish B-cell responsiveness to glucose in human islets by way of a glucose-fatty acid cycle.
Abstract: We previously demonstrated in the rat that long term exposure to fatty acids inhibits B-cell function in vivo and in vitro. To further assess the clinical significance of these findings, we tested in human islets the effects of fatty acids on glucose-induced insulin release and biosynthesis and on pyruvate dehydrogenase (PDH) activity. Human islets were obtained from the beta-Cell Transplant Unit (Brussels, Belgium). Exposure to 0.125 mmol/L palmitate or oleate for 48 h during tissue culture (RPMI-1640 and 5.5 mmol/L glucose) inhibited the postculture insulin response to 27 mmol/L glucose by 40% and 42% (P < 0.01 for difference). Inhibition was partly prevented by coculture with 1 mumol/L etomoxir, a carnitine-palmitoyl-transferase-I inhibitor (P < 0.05 for effect of etomoxir). Inhibitory effects on glucose-induced insulin secretion by previous palmitate were additive to the inhibitory effects exerted by previous high glucose (11 and 27 mmol/L). Palmitate-induced inhibition of insulin secretion was evident after exposure to 25 mumol/L added fatty acid. The insulin content of islets exposed to fatty acids was significantly reduced, and glucose-induced proinsulin biosynthesis was inhibited by 59% after palmitate addition and by 51% after oleate exposure (P < 0.01). These effects were partly prevented by etomoxir (P < 0.05). The activity of PDH in mitochondrial extracts of islets preexposed for 48 h to palmitate was decreased by 35% (P < 0.05) vs. that in control islets, whereas the activity of PDH kinase (which inactivates PDH) was significantly increased in the same preparations (P < 0.05). The effects of ketones were tested by 48-h exposure to beta-hydroxybutyrate (beta-D-OHB). Ten millimoles of D-beta-OHB per L inhibited the subsequently tested insulin response to 27 mmol/L glucose by 56% (P < 0.001). Half-maximal inhibitory effects of D-beta-OHB on insulin secretion and insulin content were seen at concentrations between 0.5-2.5 mmol/L. Inhibition by D-beta-OHB was partially reversed by etomoxir, whereas exposure to D-beta-OHB failed to affect PDH and PDH kinase activities. We conclude that fatty acids as well as ketone bodies diminish B-cell responsiveness to glucose in human islets by way of a glucose-fatty acid cycle. Increased plasma concentrations of fatty acids and ketones are likely to be important factors behind the negative influences on B-cell function exerted by a diabetic state in both type 1 and type 2 diabetes.

Journal ArticleDOI
TL;DR: Although GH has beneficial effects on central adiposity and lipid fractions, it is also associated with a decrease in IS; these effects may vary between individuals.
Abstract: GH deficiency is associated with increased cardiovascular morbidity, which may be determined by alterations in vascular risk factors. We report the effect of partially treated hypopituitarism and subsequent GH replacement (mean dose, 0.2 IU/kg.week) on putative cardiovascular risk factors in 22 nondiabetic hypopituitary subjects in a 6-month, double blind, controlled study (active/placebo ratio, 11:11). All patients were subsequently treated with GH for a further 6 months. Total fat, percent body fat, and central fat were measured by dual energy x-ray absorptiometry. The hypopituitary patients had increased percent fat (P = 0.03) and central fat (P < 0.01) compared with body mass index-matched controls. Before GH treatment, fasting (total) and specific insulin positively correlated with body mass index (P = 0.02 and P < 0.001, respectively), waist/hip ratio (P = 0.05 and P = 0.01), and central fat (P = 0.03 and P = 0.003). Specific insulin and insulin sensitivity (IS), calculated by homeostatic model of assessment, were related to total fat (P < 0.001 and P = 0.02). GH treatment for 6 months led to a reduction in total fat (P < 0.02), percent fat (P = 0.002), central fat (P = 0.012), waist/hip ratio (P < 0.05), total cholesterol (P = 0.03), and apolipoprotein-B (P = 00001), as well as a decrease in the IS from 36.9% (range, 12-100%) to 25% (range, 2.5-55%; P = 0.0002). This was paralleled by a rise in fasting (total) and specific insulin (P = 0.016 and P = 0.002). The degree of correlation among indices of IS, body composition, and fat distribution increased after GH treatment. Fasting plasma glucose rose significantly, but was within the reference range. During 12 months of GH therapy, a significant increase in serum lipoprotein-(a) was observed (P < 0.05). Although GH has beneficial effects on central adiposity and lipid fractions, it is also associated with a decrease in IS; these effects may vary between individuals.