Showing papers by "University of Texas Southwestern Medical Center published in 1973"
TL;DR: In both groups, vascular resistance to infused angiotensin II (more than 8 ng/kg/min required to elicit a pressor response of 20 mm Hg in diastolic pressure) was demonstrated as early as the 10th wk of pregnancy, with a clear separation of the two groups by the 22nd wk.
Abstract: The present study was designed to ascertain sequentially the pressor response to angiotensin II in young primigravid patients throughout pregnancy in order a) to define when in pregnancy resistance to the pressor effects of angiotensin II develops; b) to define the physiologic sequence of events leading to this resistance; and c) to ascertain whether sensitivity to infused angiotensin II could be detected before the onset of clinical signs of pregnancy-induced hypertension. With this prospective approach, two separate groups of patients were defined. The first group of patients remained normal throughout pregnancy. The second group consisted of those patients who, while clinically normotensive during the initial phase of the study, ultimately developed hypertension of pregnancy.192 patients were studied; of these, 120 patients remained normotensive and 72 developed pregnancy-induced hypertension. In both groups, vascular resistance to infused angiotensin II (more than 8 ng/kg/min required to elicit a pressor response of 20 mm Hg in diastolic pressure) was demonstrated as early as the 10th wk of pregnancy. In the group that remained normotensive, maximum mean vascular resistance occurred at 18-30 wk of pregnancy, (mean pressor dose required being 13.5 to 14.9 ng/kg/min). In those subjects who developed pregnancy-induced hypertension, the mean maximum dose required was 12.9 ng/kg/min, which was observed at the 18th wk of pregnancy. By the 22nd wk there was a clear separation of the two groups, with the mean dose requirement of the subjects destined to develop hypertension being progressively less than that of those who remained normal. The difference between the two groups became significant (P < 0.01) by 23-26 wk of pregnancy. Among patients requiring more than 8 ng/kg/min on one or more tests done between wk 28-32, 91% remained normotensive. Conversely, during the same time period among patients requiring less than 8 ng/kg/min, on at least one occasion, 90% developed pregnancy-induced hypertension.
1,177 citations
TL;DR: The purpose of the present study was to investigate the mechanisms by which estrogen production arises in the human female following the menopause, and the results suggest an increase in conversion of A to E1 with age.
Abstract: The purpose of the present study was to investigate the mechanisms by which estrogen production arises in the human female following the menopause. The possibilities considered were a) glandular secretion of estrone (E1) or estradiol (E2), b) the peripheral aromatization of circulating androstenedione (A), or c) the aromatization of other plasma precursors of estrone or estradiol. Studies were carried out in 6 postmenopausal women in which the following were measured: the plasma production rate of A (PRPA), the fraction of plasma androstenedione which was converted to estrone as measured in urine, and in blood, , and the total estrone production rate as measured by the urinary method (PRE1). The mean PRPA, 1.75 mg/24 hr, was about one-half of that observed in premenopausal women and arose principally from the adrenal glands. The mean transfer constant, value was 0.027, which is about twice the value obtained in premenopausal women, suggesting an increase in conversion of A to E1 with age. The results sugg...
875 citations
TL;DR: The activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase is suppressed in human fibroblasts cultured in the presence of serum and the factor responsible for the suppression is present in the sera of at least four mammalian species, and in human serum it is found in the low-density lipoproteins.
Abstract: The activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (EC 1.1.1.34), the rate-limiting enzyme of hepatic cholesterol biosynthesis, is suppressed in human fibroblasts cultured in the presence of serum. This enzyme activity increases by more than 10-fold after the removal of serum from the medium. The rise in enzyme activity requires de novo protein synthesis and is not accompanied by changes in the activities of several other cellular enzymes. The factor responsible for the suppression of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity in cultured fibroblasts is present in the sera of at least four mammalian species, and in human serum it is found in the low-density lipoproteins. Human high-density lipoproteins, very low-density lipoproteins from chicken egg yolk, and the fraction of human serum containing no lipoproteins do not suppress the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase.
329 citations
TL;DR: 3-Hydroxy-3-methylglutaryl-CoA reductase, the rate-controlling enzyme of cholesterol biosynthesis in rat liver, has been solubilized and purified 130-fold from rat liver microsomes and is the first solubILized microsomal enzyme reported to be cold-sensitive.
235 citations
TL;DR: Short-latency brain potentials, probably medullary in origin, in response to low-frequency sounds, were recorded from scalp electrodes and hold considerable promise for objective clinical assessment and basic research of the lower auditory brain stem.
229 citations
TL;DR: Feeding breast or soy milk in place of proprietary liquid cow milk from birth to 6 months did not affect the development of childhood allergy, and the cow group showed allergy earlier than the breast group.
Abstract: Seventeen hundred and fifty-three infants fed breast, soy, or cow milk from birth to 6 months of age were followed for varying periods to 7 years to observe the development of childhood allergy. There were 45.8 per cent with an immediate family history of allergy, 15.6 per cent with a remote history, and 38.6 per cent with a negative history. Allergy occurred in 218 (12.4 per cent), 132 males, 86 females. The development of allergy was similar in the 3 milk groups. The cow group showed allergy earlier than the breast group. Diet did not affect the incidence of the allergic diseases. In 218 allergic children, gastrointestinal allergy occurred in 13 per cent, atopic dermatitis in 33 per cent, urticaria in 8.0 per cent, allergic rhinitis in 50 per cent, and asthma in 43 per cent. Feeding egg yolk before 3 weeks of age or after 6 months of age did not affect the development of allergy. Allergy to soy milk occurred in 0.5 per cent; to cow milk, in 1.8 per cent. The incidence of allergy by family history showed significant differences: immediate, 15.6 per cent; remote, 12.1 per cent; and negative, 8.8 per cent. In the immediate group, allergy occurred earlier and asthma and allergic rhinitis more often. Feeding breast or soy milk in place of proprietary liquid cow milk from birth to 6 months did not affect the development of childhood allergy.
228 citations
TL;DR: The data obtained demonstrate that surprisingly brief periods of starvation and refeeding exert dramatic effects on glucose and fatty acid metabolism in the intact animal and that generally synchronous changes occur in the ketogenic and gluconeogenic capacities of the perfused liver.
217 citations
TL;DR: The results indicate that Eb or Tp inhibited release of LH in castrate rats of both sexes, and males were more sensitive to the inhibitor effect of the low dose of Tp than females.
Abstract: The effects of single sc injections of various doses of estradiol benzoate (Eb) and testosterone propionate (Tp) on plasma levels of LH, FSH and prolactin have been reinvestigated in castrate rats of both sexes. Our results indicate that Eb or Tp inhibited release of LH in castrate rats of both sexes. Males were more sensitive to the inhibitor effect of the low dose of Tp than females. The steroids also lowered plasma FSH levels in spayed females; however, in castrated males Eb stimulated FSH release and a decrease in FSH followed the injection of only the highest dose (2 mg) of Tp. Eb and Tp had a synergistic effect in inhibiting FSH release in the male. Both steroids stimulated release of prolactin in castrate males and females (no sex difference in release of prolactin in response to Eb was observed; however, males appeared more sensitive to Tp treatment). Single injections of progesterone (P) in spayed females produced variable results. High doses inhibited LH release and elevated prolactin levels. Ef...
145 citations
TL;DR: The measurement of glomerular filtration rate (GFR) is an important index in the evaluation and follow-up of patients with renal disease and transplant recipients and a new technique for the administration of iothalamate has been introduced.
140 citations
TL;DR: Results demonstrate that uptake of short-chain fatty acid monomers is rate limited by the lipid cell membrane but diffusion through the unstirred water layer becomes increasingly rate limiting as the chain length increases.
139 citations
TL;DR: Initiation of the rapid phase of testicular growth at 25 days could be correlated with the elevations of serum FSH and prolactin levels, and rapid growth of sex accessories began somewhat later in the presence of continued relatively high prol actin levels and falling levels of FSH.
Abstract: Serum levels of FSH, LH and prolactin were determined during development in male rats. Blood was collected from the trunk after decapitation. Prolactin levels were very low at 15 and 20 days of age, underwent an initial rise at 25 days, and then remained relatively constant until 50 days. A secondary increase occurred thereafter to reach maximal adult values at 90 days. Serum FSH was readily detectable at 15 and 20 days, rose to a peak at 25 and 30 days and then declined back to the original levels by 60 days. It remained relatively constant thereafter. On the other hand, serum LH levels underwent a very gradual increase from 15 days to reach a maximum at 70 days which was similar to levels found in adults. Initiation of the rapid phase of testicular growth at 25 days could be correlated with the elevations of serum FSH and prolactin levels. Rapid growth of sex accessories began somewhat later in the presence of continued relatively high prolactin levels and falling levels of FSH. Later growth of the sex ...
TL;DR: If complete heart block develops in such cases in association with an acute myocardial infarction, even though transient, permanent pacing should be tolerated, patients with this form of block should have temporary standby pacemakers inserted.
Abstract: Of 425 patients with acute myocardial infarction admitted to a coronary-care unit 77 (18 per cent) had ventricular conduction blocks. Complete heart block developed in 43 per cent with right-bundle-branch block and left-axis deviation, in 17 per cent with left-bundle-branch block, and in 6 per cent without ventricular conduction blocks. In-hospital mortality was 30 per cent in patients with and 14 per cent without ventricular conduction block. Late sudden death occurred in five of six patients with right-bundle-branch block and left-axis deviation who had transient complete heart blocks during myocardial infarction, whereas eight similar patients with complete heart block with permanent pacing were alive. These findings suggest that patients with this form of block with an acute myocardial infarction should have temporary standby pacemakers inserted. If complete heart block develops in such cases in association with an acute myocardial infarction, even though transient, permanent pacing should be...
TL;DR: The apparent normalcy of Sertoli cell tight junctions after vasoligation supports the view that blockage of testicular secretions distal to the epididymis is relatively innocuous.
Abstract: The permeability of Sertoli cell tight junctions to lanthanum administered during fixation has been compared in rats after ligation of the ductus deferens and after ligation of the ductuli efferentes. In both control and vasoligated testes, lanthanum penetrated only short distances into the Sertoli cell tight junctions before stopping abruptly. The tight junction, consisting of numerous pentalaminar fusions of contiguous Sertoli cell membranes, prevented diffusion of lanthanum into the adluminal compartment of the seminiferous epithelium. In rats with ligated ductuli efferentes, lanthanum completely permeated many Sertoli cell tight junctions and occupied intercellular spaces of the adluminal compartment. In spite of their newly acquired permeability to lanthanum, tight junctions retained characteristic ultrastructural features, including numerous membrane fusions. When lanthanum-filled tight junctions were sectioned en face, membrane fusions appeared as pale lines in lakes of electron-opaque tracer. These linearly extensive fasciae occludentes occasionally ended blindly, suggesting that lanthanum may have traversed the junction by diffusing around such incomplete barriers. The increased permeability of Sertoli cell tight junctions after efferent ductule ligation, which caused rapid testicular weight gain followed by atrophy, indicates that tight junctions are sensitive to enforced retention of testicular secretions inside the seminiferous tubules. The apparent normalcy of Sertoli cell tight junctions after vasoligation, which had no effect on testis weight, supports the view that blockage of testicular secretions distal to the epididymis is relatively innocuous.
TL;DR: It has been well documented that ACTH is able to prevent the extensive atrophy of the cells in the adrenal zona fasciculata which occurs after hypophysectomy, but less is known about the trophic effect of ACTH on the components of steroid hormone synthesis.
Abstract: ACTH can stimulate adrenal steroid production within a short time period, or maintain corticosteroidogenesis over long periods of time. The mechanism of the short-term, or tropic, action of ACTH seems to involve the synthesis of a short-lived protein which can specifically stimulate glucocorticoid production within 15 min,'.* presumably at the rate-limiting step, the side-chain cleavage of cholesterol to pregnen~lone.~ The long-term, or trophic, action of ACTH involves the maintenance of both adrenocortical integrity and an increased steady-state secretion of glucocorticoids. While the puzzle of the tropic effect of ACTH may be closer to solution, less is known about the trophic effect of ACTH on the components of steroid hormone synthesis. It has been well documented that ACTH is able to prevent the extensive atrophy of the cells in the adrenal zona fasciculata which occurs after hypophysectomy.' At the fine structural level, however, studies reported within the past 15 years on the effect of hypophysectomy and ACTH treatment have been, in general, contradictory and inconclusive (they are extensively reviewed by Idelman'). Recently, Canick and Purvis' investigated the trophic effect of ACTH on the size and number of mitochondria of the zona fasciculata. It was reported that ACTH appears to maintain mitochondrial size and number by controlling mitochondrial growth and division. Nussdorfer and colleagues' have shown that the administration of ACTH to normal rats over long time periods caused substantial proliferation of the smooth endoplasmic reticulum (SER) as well as a small but significant increase in mitochondrial volume. Both the mitochondria and the SER are directly involved in corticoid synthesis, since all the enzymes in the oxidative pathway from cholesterol to corticoids are located on these membranes (this is reviewed by Savard'). Kimura\" has investigated changes in various adrenal enzymes after hypophysectomy and subsequent ACTH treat-
TL;DR: There is a definite relationship between plasma testosterone levels and Leydig cell fine structure in seasonally breeding hyrax, and average Leydigs cell volume showed significantly positive correlation with plasma testosterone level.
Abstract: Seasonal changes in plasma testosterone levels and in various testicular parameters were studied in 41 adult male rock hyrax (Procavia habessinica). Among animals collected during the annual breeding season, testis weights and plasma testosterone levels were approximately five times greater than among animals collected outside the breeding season. Light microscopic measurements showed that increase in testis weight was largely due to enlargement of the seminiferous tubules. Histological sampling techniques indicated no significant change in Leydig cell numbers. Leydig cell size increased during the breeding season, and average Leydig cell volume showed significantly positive correlation with plasma testosterone level. With the electron microscope, Leydig cell hypertrophy was seen to involve changes in quantity and structure of several cytoplasmic constituents. Lipid droplets disappeared and smooth endoplasmic reticulum (SER) spread dramatically as the cells increased in size. In contrast to the sparse and heterogeneous assemblage of irregularly tubular and cisternal SER seen in nonbreeding animals, the extensive masses of SER in breeding animals appeared as relatively straight, unbranched tubules of uniform diameter. Peculiar membranous structures, possibly derived from the SER, were abundant in the periphery of Leydig cells from animals with high plasma testosterone levels. These findings suggest that there is a definite relationship between plasma testosterone levels and Leydig cell fine structure in seasonally breeding hyrax.
TL;DR: The propranolol inhibition suggests a beta-adrenergic component to this type of renin release and the potential for a clinically efficacious drug interaction.
Abstract: The capacity of the vasodilating drugs, minoxidil and hydralazine, for inducing renin release was characterized in rats according to chronology and dose response. Propranolol inhibition of this renin release was also characterized and related to serum levels of propranolol. Minoxidil and hydralazine (1.0 mg/kg) induced sevenfold elevations of serum renin activity. Treatment with propranolol, resulting in plasma propranolol concentrations as low as 50 ng/ml, impaired vasodilatory drug-induced renin release. The propranolol inhibition suggests a beta-adrenergic component to this type of renin release and the potential for a clinically efficacious drug interaction.
TL;DR: The data obtained in this study demonstrate that during myocardial ischemia epicardial sites of S-T segment elevation are sites of pronounced subendocardial and epicardia and of anaerobic metabolism.
Abstract: Canine left ventricular wall metabolites (ATP, creatine phosphate, glycogen, glucose, glucose-6-phosphate, and lactate) were assessed in the ischemic region of the wall after 17 minutes of ligation of the left anterior descending coronary artery at its midlevel. Variations in the degree of lactate accumulation were found between different sites in the same ischemic region and between the outer and the inner left ventricular wall at the same site. High levels of lactate were associated with S-T segment elevation in the epicardial electrocardiogram, but no lactate accumulation or only mild lactate accumulation was found at isoelectric sites. Lactate accumulation at isoelectric sites was higher in the outer wall than it was in the inner wall; the opposite tendency was observed at sites of S-T segment elevation. In addition to high lactate levels, sites of S-T segment elevation demonstrated a more pronounced depletion of ATP and creatine phosphate, indicating not only a marked anaerobic glycolysis but also a more pronounced overall anaerobic stress. No relationship was found, however, between the absolute magnitude of S-T segment elevation and the degree of lactate accumulation or ATP depletion at sites of S-T segment elevation within the ischemic region. The data obtained in this study demonstrate that during myocardial ischemia epicardial sites of S-T segment elevation are sites of pronounced subendocardial and epicardial ischemia and of anaerobic metabolism.
TL;DR: The results suggest that immunologically activated cells are more likely to cross the placenta than normal cells and that this greater mobility may not be related to the immunologic specificity of the activated cells.
Abstract: Without altering the structural integrity of the placenta by irradiation or drugs, we have shown that it is possible to immunize females both adoptively and actively against the paternally inherited transplantation antigens of their fetuses. Such immunization causes a high incidence of runt disease among the litters. Although the putative chimeric status of the affected offspring has yet to be confirmed, the results of our experiments support the thesis that runt disease is caused by the activities of "unwanted" immigrant lymphocytes from the maternal circulation. Our results suggest that immunologically activated cells are more likely to cross the placenta than normal cells and that this greater mobility may not be related to the immunologic specificity of the activated cells. Two factors may have contributed to the apparent failure of numerous previous attempts to demonstrate the capacity of transplantation immunity to affect the well-being of a fetus or, more correctly, its placenta, in the way that might be expected of a homograft. (i) Investigators were preoccupied with obtaining a classic type of rejection, in utero, analogous to the rejection of an orthotopic skin homograft. The birth of consistently healthy-looking litters, interpreted as a failure of the experiment, convinced the investigators of the efficacy of nature's solution of the homograft problem and there was no reason for them to suspect its possible limitations. Observation of the litters for several weeks might have uncovered the phenomenon of maternally induced runt disease. (ii) Most investigators resorted to hyperimmunization of the mothers. This would have facilitated the synthesis of protective isoantibodies capable of interfering with the expression of the potentially harmful cellular immune response (6). Ever since the abnormalities of runt disease were first described they have repeatedly been compared to those observed in patients with certain lymphomas (17). Various theories have been propounded as to how maternally transmitted graft-versus-host reactivity might lead to the development of these tumors. In mice it has been established that graft-versus-host reactivity may result in a high incidence of lymphomas (18). Recent analysis indicates that this graft-versus-host reactivity unmasks and activates normally latent and undemonstrable oncogenic viruses (19). The work we describe in this article may have some relevance to the possible clinical significance of transplacental cellular mobility in man. We suggest that the relatively high incidence of lymphomas in children might also be, in part at least, due to unmasking of oncogenic viruses by subclinical graft-versus-host reactivity mediated by immunocompetent cells of maternal origin. The statistical evidence that male infants are at greater risk than females (20) is concordant with our observation that maternally induced runts include a significantly higher proportion of males than females (10).
TL;DR: A method for measuring aldosterone concentration has been improved by extracting the steroid from plasma with an antibody prior to radioimmunoassay, which eliminates chromatography and enables one technician to process 80–120 specimens each week.
Abstract: A method for measuring aldosterone concentration has been improved by extracting the steroid from plasma with an antibody prior to radioimmunoassay. Precision, sensitivity and specificity were comparable in our laboratory to a method using paper chormatography and to published data for other methods. Duplicate specimens assayed with both methods gave a correlation of r = 0.91 (p < 0.005). This method eliminates chromatography and enables one technician to process 80–120 specimens each week.
TL;DR: The results demonstrate that fixation of tissue in osmic acid followed by determination of mean basement membrane thickness reveals significant basement membrane thickening in over 90 per cent of diabetic subjects.
Abstract: 1. Several methods of quantifying muscle capillary basement membrane width have been evaluated with the aim of determining whether variations in technic may influence the sensitivity of detecting significant capillary basement membrane thickening in diabetic subjects. 2. The results demonstrate that fixation of tissue in osmic acid followed by determination of mean basement membrane thickness reveals significant basement membrane thickening in over 90 per cent of diabetic subjects. 3. The error in estimation of mean basement membrane width due to oblique sectioning of diabetic capillaries is shown to be small, i.e. approximately 10 per cent. By contrast, measuring only the minimum basement membrane thickness of a capillary may underestimate diabetic basement membrane hypertrophy by from 20 to 40 per cent. 4. As compared to osmic acid fixation, glutaraldehyde leads to a very significant increase in the basement membrane width affecting normal capillaries relatively more than diabetic capillaries. 5. As a result, either fixation in glutaraldehyde or measurement of minimum basement membrane thickness may lead to a marked decrease in the sensitivity of the quantitative basement membrane technic. A procedure that employs both glutaraldehyde fixation and measurement of only minimum basement membrane width would appear to detect microangiopathy in only 45 per cent of diabetic subjects.
TL;DR: In dogs fat absorption is accompanied by prompt and substantial increases in plasma glucagon and GLI and a small transient rise in insulin and the evidence favors an enterogenic signal to the islets of Langerhans rather than their stimulation by chylomicrons.
Abstract: The effects of a fat meal upon plasma insulin, glucagon, and glucagon-like immunoreactivity (GLI) have been studied in conscious dogs and in human volunteers. In dogs the intraduodenal instillation of 10 g/kg of peanut oil was accompanied by increases in the mean plasma levels of all three polypeptides that averaged 5 muU/ml, 107 pg/ml, and 2.1 ng/ml, respectively. 3 g/kg of peanut oil, when emulsified with egg yolk, elicited a much greater response of the three hormones, and a physiologic dose of 1 g/kg in emulsified form also caused a significant rise in glucagon and GLI. The islet cell hormone response was not ascribable to chylomicronemia since intravenous infusion of canine chyle failed to stimulate glucagon secretion; moreover, in dogs with a thoracic duct fistula in which chyle was excluded from the circulation, the intraduodenal administration of a fat meal elicited the normal islet cell hormone response, as well as a rise in GLI. 10 g/kg of medium-chain triglycerides failed to elicit these same responses. In six human volunteers the oral administration of 3 g/kg peanut oil was accompanied by increments of 2 muU/ml, 26 pg/ml, and 1.5 ng/ml in the mean levels of insulin, glucagon, and GLI. The changes in insulin and glucagon in man were neither statistically significant nor biologically impressive. It is concluded that in dogs fat absorption is accompanied by prompt and substantial increases in plasma glucagon and GLI and a small transient rise in insulin. The evidence favors an enterogenic signal to the islets of Langerhans rather than their stimulation by chylomicrons. Pancreozymin is qualified to serve as such a signal. The physiologic implications of this study are considered.
TL;DR: Microangiographic and histologic studies demonstrated that intraosseous and intrapulpal circulation to the mobilized maxillary segments were maintained by the experimental flap designs which maintained intact soft tissue; the fragments healed by osseous union within six weeks without immobilization of the mandible.
Abstract: Adult Rhesus monkeys were used as experimental models to investigate revascularization and bone healing in different single-stage anterior, posterior and total maxillary osteotomy techniques.
Microangiographic and histologic studies demonstrated that intraosseous and intrapulpal circulation to the mobilized maxillary segments were maintained by the experimental flap designs which maintained intact soft tissue; the fragments healed by osseous union within six weeks without immobilization of the mandible.
The treatment of many severe dental-facial deformities is difficult and challenging. Functional and stable occlusions with facial balance and harmony have been attained in many adult patients by maxillary osteotomy techniques.
The Rhesus monkey serves as an excellent experimental model to develop new biologically sound maxillary surgical orthodontic techniques.
TL;DR: The response to preoptic stimulation was dependent on the current strength and the blockade could be reversed by the administration of either L-dopa or dihydroxyphenylserine shortly after treatment with alpha-methyl-p-tyrosine to reverse the blockade of catecholamine or norepinephrine synthesis.
Abstract: Electrochemical stimulation of the preoptic or median eminence-arcuate region of proestrous rats anesthetized with ether led to an elevation of plasma LH within an hour following stimulation. The elevation was greater following median eminence-arcuate stimulation than after preoptic stimulation and the response to preoptic stimulation was dependent on the current strength. The elevation in plasma LH induced by medial preoptic stimulation was partially blocked by pretreatment of the animals with alpha-methyl-ptyrosine to block catecholamine synthesis. The blockade could be reversed by the administration of either L-dopa or dihydroxyphenylserine shortly after treatment with alpha-methyl-p-tyrosine to reverse the blockade of catecholamine or norepinephrine synthesis, respectively. Pretreatment of the animals with diethyldithiocarbamate to lower norepinephrine levels selectively also blocked the response to preoptic stimulation and this blockade could be partially reversed by the administration of dihydroxyph...
TL;DR: To determine whether cholinergic pathways are involved in central nervous system (CNS) control of gonadotropin and prolactin release, atropine sulfate was injected sc or directly into the third ventricle (250 μg) in order to block Cholinergic receptors.
Abstract: To determine whether cholinergic pathways are involved in central nervous system (CNS) control of gonadotropin and prolactin release, atropine sulfate was injected sc (70 mg/100 g body wt) or directly into the third ventricle (250 μg) in order to block cholinergic receptors. The alkaloid injected by either route at 11:45–1:15 on the day of proestrus blocked the surges of LH, FSH and prolactin during the afternoon. Following orchidextomy, sc atropine prevented the elevation of plasma FSH and LH that normally occurred 16 and 24 hr post—castration. When atropine was injected into the third ventricle 24 hr post—orchidectomy, plasma LH decreased significantly within 2 hr. At 3–5 weeks post—ovariectomy or orchidectomy, sc injection of the alkaloid decreased plasma LH within 1 hr in females but the decrease was only apparent after 24 hr in the castrate males. Since injection of synthetic LHreleasing factor (LRF) elevated plasma LH in both proestrous females and castrate males injected sc with atropine, the actio...
TL;DR: It is demonstrated that serum from patients with acute viral hepatitis, chronic Australia antigenemia, common bile duct obstruction, primary biliary cirrhosis, hepatic necrosis secondary to halothane, and alcoholic Cirrhosis suppresses DNA synthesis by stimulated normal lymphocytes.
TL;DR: The results suggest that the sensitivity of the hypothalamic pituitary unit to the negative feedback of testosterone declines during sexual development and that this change, which is especially noticeable at the time of puberty, is noticed.
Abstract: Male rats were castrated at different ages and injected sc once daily for 2 days with either oil or various doses of testosterone propionate (TP). Castration elevated serum gonadotropins at all ages studied from day 15 to clay 88, but the response was maximal for LH at 58 days and minimal at 15 days. The elevation of FSH was minimal at 88 days but similar at other ages. Whereas 10 μg/100 g body wt of TP were sufficient to prevent the rise in serum FSH and LH which occurred 2 days after castration in 15-day-old rats and 10 M-g were still effective in 28-day-old animals, the suppressibility of serum gonadotropins decreased with age and by 58 days the 10 μg/100 g body wt dose was no longer effective. Higher doses of TP suppressed the increase in serum LH and FSH at all ages studied. The results suggest that the sensitivity of the hypothalamic pituitary unit to the negative feedback of testosterone declines during sexual development and that this change, which is especially noticeable at the time of puberty, ...
TL;DR: The reported control mechanism for triglyceride biosynthesis is discussed in relation to the regulation of fatty acid uptake and release in adipose tissue and the absorption and metabolism of triglycerides by the intestinal mucosa.
TL;DR: The pregnancy experiences for women with sickle cell trait were not different from those of black women whose red cells do not sickle except for twice the frequency of significant bacteriuria and the only major cause for special concern is their potential for transmission of one gene for sickling to the off spring.