Showing papers in "International Journal of Obesity in 1985"

Quetelet's index (W/H2) as a measure of fatness

Abstract: A weight-height index of adiposity should indicate the relative fatness of subjects of differing height unless obesity is itself correlated with height. The average body fat among adult women attending a hospital outpatient clinic for obesity was 40.5 percent of body weight. The height of an unselected series of 286 of these outpatients was found to be similar to that of the general population of women of similar age, which indicates that obesity in adult women is not significantly related to height. Body composition was measured by body density, body water and body potassium in a series of 104 female and 24 male subjects aged 14-60 years. In both sexes density, water and potassium gave progressively higher estimates of body fat (kg), and there was a significant difference between the values by different methods. The average of the estimates by these three methods was taken to be the 'true' value for each individual (F kg). Regression of F/H2 on W/H2 (Quetelet's index) gave a correlation coefficient of 0.955 for women and 0.943 for men. The deviation of the body fat estimated from Quetelet's formula from the 'true' value was not much greater than that when density, water or potassium were used as a basis for estimating body fat. It is concluded that Quetelet's formula is both a convenient and reliable indicator of obesity.

Health implications of obesity: an NIH consensus development conference

Abstract: A Consensus Development Conference on the Health Implications of Obesity was held in February 1985 at the National Institutes of Health in Bethesda, Maryland, USA. After presentations by 19 experts in relevant subject areas, a panel of 15 impartial senior level professionals presented their consensus of findings and recommendations. This paper summarizes the results of the conference and provides reference tables of body mass index (BMI) values and weight goals, along with nomograms of the BMI determined from height and weight scales, to show comparisons with weight goals. The goals are taken from two widely available tables of mortality data by weight. These reference aids are included to illustrate the potential clinical value of wider use of the BMI, as recommended in the conference.

Effect of dietary fat content on the incidence of obesity among ad libitum fed mice.

Abstract: Graded increments in the fat-to-carbohydrate ratio of the diet elicited a gradual, but reversible increase in the average mass of body fat maintained by adult female (CDI) albino mice under ad libitum feeding conditions. In addition, the inter-individual variability in the animals' fat mass was greatly magnified by diets with a substantial fat content (greater than 30 percent of calories). As a result, the incidence of obesity (defined as one third or more of body weight as fat) increased progressively from 0 percent to 35 percent when the diet's fat content was varied from 1 percent to 64 percent of its total energy content. A state of weight maintenance can only become established when the relative rates of glucose and fatty acid oxidation are proportional, on average, to the carbohydrate-to-fat ratio of the diet. When diets with a relatively high fat content are consumed, a considerable enlargement of the adipose tissue mass appears to be necessary in many animals before weight maintenance becomes spontaneously established. It is proposed, therefore, that changes in the adipose tissue mass, along with shifts in the range in which glycogen levels are maintained, and other adaptive changes, contribute to bring about rates of fat oxidation commensurate with a diet's fat content. This impact of dietary composition on body composition may be a factor contributing to the increased incidence of obesity in affluent populations consuming diets with a substantial fat content.

Gonadal influences on adiposity.

Abstract: Gonadal steroids affect energy balance and adiposity in a variety of mammalian species. For example, estradiol acts via multiple, redundant mechanisms to reduce body weight and adiposity. The steroid can act directly in the brain to decrease food intake and stimulate voluntary exercise. Sex hormones may act concurrently in non-neural peripheral tissues to alter metabolic processes and energy balance. White adipose tissue estrogen receptors may mediate estradiol-induced decreases in lipoprotein lipase activity and lipid storage. Finally, estradiol increases energy expenditure independent of any effects on voluntary exercise. Brown adipose tissue is a potential site for estradiol-induced thermogenesis.

Prediction of body fat by skinfold caliper: assumptions and cadaver evidence

Abstract: A series of assumptions required for use of skinfold calipers for the estimation of human body composition is examined in terms of direct evidence from the measurement and dissection of 6 male and 7 female cadavers. Skinfold compressibility showed significant inter-subject and inter-site differences with the highest values (64.7 percent and 63.8 percent) at the spinale and biceps sites and the lowest (33.6 percent and 34.4 percent) at the front thigh and medial calf. Skin thickness as a percentage of skinfold thickness was highest at the subscapular site (28.1 percent). Adipose tissue patterning showed great variability, indicating the importance of using skinfold caliper readings from a variety of different sites including upper limb, lower limb and trunk. Further sources of error include variability in fat content of adipose tissue (estimated at 20 percent in our sample) and in the internal and subcutaneous fat deposition. Recommendations for the use of skinfold calipers to assess adiposity and monitor change are made in the light of these findings.

Insulin-mediated glucose metabolism in the relationship between dietary intake and sympathetic nervous system activity.

Abstract: The data reviewed here demonstrate a role for insulin-mediated glucose metabolism in the relationship between fasting, carbohydrate intake, and sympathetic activity. A model relating insulin-mediated glucose metabolism to sympathetic nervous system activity during fasting and carbohydrate feeding is presented.

A controlled trial of naltrexone in obese humans.

Abstract: Based on reports that opiate antagonists can curtail short-term eating in several species including humans, the efficacy of naltrexone in promoting weight loss by obese subjects was examined. Naltrexone, a long-acting oral opiate antagonist, was studied in a randomized parallel double-blind placebo controlled ten week trial in 27 females and 14 males who were 30-100 percent overweight. Subjects on naltrexone lost an average of 1.8 kg and placebo subjects lost 1.5 kg, with no significant difference between groups. Three subjects who took naltrexone had elevations of liver transaminases, two times higher than normal. In the present study naltrexone at a daily dosage of 200 mg did not appear to have efficacy in producing weight loss after eight weeks of treatment. Studies of the effects of naltrexone at higher dosage or for longer periods should monitor hepatic function.

Factors influencing anatomic location of fat tissue in 52,953 women.

Abstract: Data from a cross-sectional, questionnaire-based study of women was undertaken to determine factors associated with the anatomic distribution of body fat. The women studied were members of TOPS, Inc. (Take Off Pounds Sensibly), a non-profit organization dedicated to weight reduction. Recent evidence suggests that anatomic location of body fat has prognostic significance for some chronic conditions. The simple ratio of waist girth to hip girth can be used to estimate the location of body fat. Using this ratio as an index we found that increased age and higher body weight were significantly associated with greater fat deposition in the waist areas as compared to the hip areas. The effects of age and current obesity level were independent and could not be accounted for on the basis of parity, menopausal status, or obesity history. Furthermore, though obesity history and parity were significantly associated with the waist-hip ratio, they were relatively unimportant, together explaining less than one percent of the observed variation in the ratio. No association could be found between body fat distribution and menopausal status. Our findings do not support previous work which suggested that menopausal status and obesity history were important determinants of body fat location.

Diet and exercise training effects on resting metabolic rate.

Abstract: The decline in resting metabolic rate (RMR) during periods of caloric restriction is a well documented phenomenon. The purpose of this study was to determine if either 30 min of daily self-selected aerobic activity (Group D) or prescribed exercise training performed every other day (Group P) for 12 weeks can prevent the decrease in RMR during caloric restriction for weight loss. Seventy-eight adult subjects (38 M, 40 F) whose weights were 15-35 percent above the upper limit for age, sex and frame were randomly assigned to three treatment groups. All three groups followed the same 1200, 1500 or 1800 kcal/d (5023, 6279, 7534 kJ) diet exchange plan. Group C (Control) followed no exercise program, while D and P exercised as described above. Maximal oxygen consumption (VO2 max, m10(2)/kg X min-1) predicted from the Bruce Test increased by 0.08 +/- 7, 9 +/- 12 and 12 +/- 9 percent in groups C, D and P, respectively. The increases for D and P were significantly higher than for C (P less than 0.01). RMR (m10(2)/kg X min-1) increased by 2 +/- 9, 4 +/- 7 and 10 +/- 9 percent in groups C, D and P respectively. The percent change for group P was significantly greater than that for groups C and D (P less than 0.05). There was a significant relationship across all subjects between the % delta in VO2 max and % delta in RMR (r = 0.307, P less than 0.01). However, the association between these two variables was stronger for females than for males.(ABSTRACT TRUNCATED AT 250 WORDS)

The relationship of enzyme activity to feeding behavior in rats: lipoprotein lipase as the metabolic gatekeeper.

Abstract: A model for peripheral modulation of feeding behavior is discussed. This model proposes that under certain genetic, hormonal or dietary conditions adipose tissue lipoprotein lipase (AT-LPL) acts as a gatekeeper directing triglyceride derived fuels to adipose tissue and away from other tissues. It is proposed that shifts in the activity of the gatekeeper enzyme LPL result in changed feeding behaviors in rodents and possibly in man. In the fafa rat, the alterations in LPL activity may play the role of a developmental trigger or initiator. In other cases, the changes in AT-LPL may be adaptive rather than initiatory and may be permissive of behaviors rather than necessary antecedents.

Fat distribution of overweight persons in relation to morbidity and subjective health

Abstract: The association between fat distribution, morbidity and subjective health was studied in 95 overweight adult men and 210 overweight adult women. Retrospective morbidity data were taken from a continuous morbidity registration made by general practitioners over a period of maximally 17 years. In addition information about subjective health and weight history was obtained from a self-administered questionnaire. Anthropometric measurements were taken and, on the basis of waist-hip and waist-thigh circumference ratios, subjects were classified into upper body segment obesity, intermediate obesity, and lower body segment obesity. It was found that, adjusted for age and body mass index, a high waist-thigh circumference ratio was a risk factor for hypertension and for gout or diabetes in women and arthrosis in men. A low waist-thigh ratio was associated with a high prevalence of varicose veins in women. The associations of waist-hips circumference ratio with morbidity were less pronounced, with the exception of hypertension in men. Information from the questionnaire revealed that persons with upper body segment obesity (especially men) felt less healthy and had more health complaints. These findings were more pronounced for subjects less than 50 years of age than for those of 50 years and older. The weight histories suggest that women with lower body segment obesity had a longer history of obesity than women with upper body segment obesity. This was not found in men. It is concluded that classification of obesity on the basis of circumference ratios is useful for the evaluation of health hazards of overweight subjects.

Adiposity, anthropometric measures, and plasma insulin levels of rhesus monkeys.

Abstract: In order to characterize spontaneous adult-onset obesity in a non-human primate model, we have studied a group of twenty-four obese and non-obese male rhesus monkeys (Macaca mulatta). The monkeys, ranging in age from 12 to 27 years, were defined as obese on the basis of tritiated water estimates of body fat content exceeding 25 percent of body weight. Although the obese and non-obese monkeys had similar crown-rump lengths, they differed significantly not only in body weight (17.0 +/- 3.2 vs 11.7 +/- 1.8 kg, X +/- s.d., P less than 0.001), and average body fat content (37.8 +/- 6.6 vs 13.2 +/- 5.4 percent, P less than 0.001) but also in midgirth circumferences (57.5 +/- 8.4 vs 34.8 +/- 6.2 cm, P less than 0.001) and abdominal (but not triceps or scapular) skinfold thicknesses (22.74 +/- 5.8 vs 9.82 +/- 1.82 mm, P less than 0.001), thus, indicating the predominantly abdominal distribution of the fat mass. A new Obesity Index Rh, for rhesus monkeys, defined as body weight divided by the square of the crown-rump length, was developed as an adaptation of obesity indices used for humans and rats. The high correlation of the Obesity Index Rh with percent body fat and its relative independence of height make possible future identification of obese rhesus monkeys on the basis of anthropometric measurements. There were slight, but not significant, differences between the obese and the non-obese groups in lean body mass (10.9 +/- 2.8 vs 8.8 +/- 1.8 kg) and in fasting plasma glucose levels (87.1 +/- 31.8 vs 63.2 +/- 7.5 mg/dl). Obese monkeys had significantly larger average fat cell sizes (1.29 +/- 0.54 vs 0.61 +/- 0.29 microgram lipid/cell, P less than 0.05) and significantly greater fat cell numbers (6.1 X 10(9) vs 2.2 X 10(9), P less than 0.01). Fat cell numbers were better correlated with body weight and total body fat parameters than fat cell size, while fat cell size was more closely associated with the log of fasting plasma insulin levels than was fat cell number. The similarities to studies in humans indicate the importance of the spontaneously obese adult rhesus monkey as an animal model in the study of obesity.

Effect of weight loss on glucose disposal in obese and obese diabetic patients.

Abstract: The purpose of the study was to examine the effect of short-term weight loss on glucose disposal and lipid oxidation in obese patients Twenty-six obese patients were divided into three groups according to their degree of glucose intolerance: normal glucose tolerance = Gp I; impaired glucose tolerance without diabetes = Gp II; diabetes = Gp III The patients submitted to an hypocaloric, high-protein diet for 8 to 45 weeks Respiratory exchange measurements were performed by means of continuous indirect calorimetry during a 100 g, 3 h oral glucose tolerance test (OGTT) before weight loss and were repeated at the end of the weight loss period, 3 to 8 weeks after the reintroduction of a balanced isocaloric diet Glucose tolerance, which was decreased in Gps II and III, improved after weight loss Glucose oxidation, which was decreased in Gps II and III showed improvement after weight reduction in both Gp II (309 +/- 23 after weight loss vs 242 +/- 20 g/3 h before, P less than 0025) and in Gp III (331 +/- 16 vs 258 +/- 41, ns) In the diabetic group (Gp III), before weight loss, a decrease in nonoxidative glucose uptake was observed, which was probably due both to a decrease in glucose storage and to the inhibition of splanchnic glucose output After weight loss, it increased significantly from 277 +/- 52 to 569 +/- 23 g/3 h (P less than 0001) Postabsorptive plasma insulin levels decreased in all groups following weight reduction When exaggerated the insulin response to the glucose load fell to normal values whereas the insulin response increased in the diabetic patients in whom it was initially blunted Lipid oxidation rates, both preload and postload, were markedly elevated before weight loss in all three groups They were substantially reduced after weight loss This study shows that a weight loss of 10 to 33 kg in obese patients promoted an increase in the subnormal glucose oxidation rate in Gp II as well as an improvement of the low nonoxidative glucose uptake in the diabetic group, thus improving their glucose tolerance There was a simultaneous reduction in lipid oxidation in both groups Furthermore, the insulin response to the glucose load, whether elevated or decreased before weight loss, tended towards normalization after weight reduction

Obesity and hypertension: long-term effects of weight reduction on blood pressure.

Abstract: Long-term follow-up studies were conducted on massively obese hypertensive subjects during and after a successful protein supplemented fast (PSMF) in order to correlate blood pressure changes with caloric intake and body weight. The blood pressures in 43 subjects were compared during rapid weight loss and at identical weights during post-fast weight gain (Study A). Blood pressures and body weights in 50 subjects were compared prior to starting PSMF and prior to restarting the program 21 months later (Study B). One hundred twenty-five compliant subjects were observed after one month of weight maintenance (Study C-1), and 39 subjects were followed during six months of weight maintenance (Study C-2). In Study A, during subsequent weight gain on an unrestricted diet blood pressure was significantly higher than at identical weight during continuous weight loss on PSMF. However, this increase in blood pressure was only approximately 30 percent of the original decrease. In Study B, weight loss and blood pressure reduction were significantly correlated. After one month of weight maintenance following continuous weight loss of 73 lb, there was no increase in blood pressure (Study C-1). A small but significant increase in blood pressure after six months (Study C-2) was associated with similar small weight increment. However, all blood pressures remained well within the normotensive range and significantly lower than control values. In this study, long-term changes in blood pressure correlated with changes in body weight.

A controlled trial using ephedrine in the treatment of obesity.

Abstract: A double-blind controlled study was performed in unselected obese outpatients to assess the effects of ephedrine on weight loss. Patients were treated for 3 months with placebo (group I), 25 mg t.i.d. or 50 mg t.i.d. of ephedrine hydrochloride orally administered (groups II and III, respectively). Dietary treatment consisted of 1000 kcal/day for females and 1200 kcal/day for males. The three groups were matched for age, sex, body mass index and pre-treatment spontaneous caloric intake. Weight loss was similar in all groups. Patients in group III (ephedrine 150 mg/day) showed significantly more side effects than the placebo group. These results do not seem to favour the hypothesis that ephedrine, a thermogenic agent, may be effective in the therapy of unselected simple obesity. On the other hand, it cannot be excluded that the drug may be useful in obese patients in whom defective thermogenesis may be clearly demonstrated.

Twenty-four-hour energy expenditure and thermogenesis: response to progressive carbohydrate overfeeding in man.

Abstract: Short-term overfeeding with carbohydrate induced a marked stimulation of energy expenditure, amounting to 33 per cent of the excess energy intake on the 7th day of overfeeding. This value is larger than that previously reported in man. Stimulation of lipogenesis and increased activity of the sympathetic nervous system seem to be the two major mechanisms which account for the stimulation of energy expenditure during carbohydrate overfeeding.

Cholesterol metabolism in lean and obese Zucker rats: effects of portacaval anastomosis.

Abstract: The effects of portacaval anastomosis (PCA) on cholesterol biodynamics of male adult (fa/fa) Zucker rats and their lean littermates were studied with an isotopic equilibrium method. Animals were fed with a sucrose-rich semi-purified diet. Obese rats were hypercholesterolemic (2.03 +/- 0.14 vs 1.06 +/- 0.7 mg/ml), had a cholesterol-enriched liver (135.3 +/- 14.5 vs 40.0 +/- 2.6 mg/liver) and accumulated cholesterol in body pools. However no difference in the rates of cholesterol absorption, synthesis, fecal elimination or transformation into bile acids distinguished obese from lean Zucker rats. In both lean and obese rats, PCA decreased cholesterolemia by about 28 per cent and liver weight by 40 per cent while the total cholesterol content of the liver was not affected. Input of synthesized cholesterol (internal secretion) was strikingly decreased by the shunt (from 13.2 +/- 0.6 and 12.6 +/- 0.7 mg/day/rat before PCA, to 8.9 +/- 0.8 and 8.6 +/- 1.0 mg/day/rat after PCA) in lean and obese rats respectively. A similar decrease was observed in the cholesterol transformation into bile acids. Since the activity of the gut for cholesterol synthesis, as shown by the fecal external secretion (cholesterol synthesized by the gut and directly eliminated in the gut and feces) was probably not modified, the reduction of internal secretion induced by PCA resulted from decreased hepatic cholesterogenesis. It is suggested that this decrease may be one of the factors involved in the lowering effect of PCA on plasma cholesterol level.

Overweight and musculoskeletal morbidity: a ten-year follow-up.

Abstract: The association of relative weight with various indices of musculoskeletal morbidity was studied in 902 Finnish white-collar and blue-collar workers. Data were collected in the years 1973 and 1983 through a postal questionnaire, by medical examination, and clinical assessment of the condition of the musculoskeletal system. In the overweight group (relative weight greater than or equal to 120 percent), higher mean levels in all musculoskeletal scores (the Musculoskeletal Symptoms Score, the Upper/Lower Extremities Score, the Low Back Score and the Musculoskeletal Findings Score) were observed, compared with the normal weight group. There was no evidence, however of rheumatic complaints in weight-bearing joints being more common in overweight individuals, contrary to the 'wear and tear' hypothesis. In a 10-year follow-up the changes in the musculoskeletal scores were analysed by stepwise multiple regression. Baseline relative weight explained 6.3 percent of the variation in the score based on clinical assessment. Neither baseline weight nor weight change were significant predictors of change in the other scores. No association was observed between overweight and lumbosacral disorders either in the cross-sectional study or in the 10-year follow-up.

Naloxone improves sleep apnea in obese humans.

Abstract: To test the hypothesis that endogenous opiates play a role in the etiology of the sleep apnea syndrome, we administered naloxone, an opiate antagonist, to ten obese humans with sleep apnea. On two separate nights we measured the frequency and severity of sleep apnea during naloxone infusion vs saline control infusion. The number of oxyhemoglobin desaturation episodes was not significantly lowered but the average maximal oxyhemoglobin desaturation fell significantly (P less than 0.01) with naloxone. The desaturation index (average maximal oxyhemoglobin desaturation times desaturations per hour) fell by 21 percent (P less than 0.05) on the night of naloxone infusion. Nine of the ten patients had a lower desaturation index with naloxone. REM sleep decreased by 80 percent (P less than 0.05) in the subjects in whom it was measured. We conclude that opiate antagonists hold promise in the treatment of sleep apnea and that the endogenous opiate system may be involved in the production of sleep apnea.

Personality traits in a group of severely obese patients: a study of patients in two self-chosen weight reducing programs

Abstract: The Karolinska Scales of Personality (KSP) test, were used in 98 obese patients. Both female and male patients showed higher scores in Somatic anxiety, Muscular tension, Impulsiveness, Monotony avoidance and lower scores in Socialization when compared to control groups for each sex. The obese patients were given the choice of treatment with either a combined behavioural modification program or jaw fixation. These groups differed significantly with regard to Psychasthenia, with higher scores in those who chose behavioural treatment, and to Monotony avoidance with higher scores in those who chose jaw fixation.

Regional differences in adipocyte metabolism and possible consequences in vivo.

Abstract: Recent studies have shown that adipose tissue metabolism varies in different regions. Thus, hormonal responsiveness and sensitivity to both lipolytic and anti-lipolytic agent is increased in abdominal as compared to femoral cells. Abdominal obesity is also associated with greater aberrations in metabolism than peripheral obesity. The increased lipolytic response in abdominal fat cells may lead to higher FFA concentrations, which may attenuate both glucose uptake and insulin clearance by the liver.

Food perceptions and preferences of obese adults: a multidimensional approach.

Abstract: Perceptions of nutritional aspects of common foods, as rated by obese and normal-weight subjects, were mapped using multidimensional scaling (MDS) procedures. The foods were rated for their perceived protein, fat and carbohydrate content, calories, and overall nutritional value. No differences in food perception or nutritional evaluation were observed among obese and normal-weight subjects. However, the two groups differed in their reported patterns of food preference. Normal-weight subjects generally reported liking foods that were also viewed as nutritious and low in energy content, whereas obese subjects showed more diverse preference profiles that were not linked to perceived nutrition. This variability of response suggests internal inconsistencies in attitude structure among obese individuals.

Alternative measurements of obesity: accuracy of body silhouettes and reported weights and heights in a Mexican American sample.

Abstract: The assessment of obesity by anthropometry or body composition in studies of chronic disease epidemiology is not always feasible. In this paper we test the accuracy and validity of two alternative methods: body silhouettes and reported weights and heights in a sample of Mexican American adults (n = 166) participating in the Diabetes Alert Study. The body silhouettes were those developed by A. Stunkard and colleagues. We compared the silhouettes obtained independently by three different observers, one with minimal experience in assessing obesity, the other two skilled in anthropometry. Correlations between the expert observers were 0.89-0.90. Those between the expert and less skilled observers were lower (0.64 to 0.85) and were better for female than male subjects. Results suggest an acceptable level of precision for persons with some training in obesity assessment. Body silhouettes compared well with the body mass index (r = 0.85 to 0.92 for the expert vs r = 0.65 to 0.84 for the less skilled observer), being higher for female subjects. The body silhouettes are thus useful for categorizing normal, overweight and obese individuals. The poorer performance on male subjects may relate to the female-like obesity depicted in both sexes in this particular set of silhouettes. A substantial proportion of subjects could not recall their weight or height. For those who could recall their measurements, accuracy was good but measurement error higher than that for measured variables. These problems of recall in this sample from rural Texas point to the potential usefulness of the body silhouette method when actual height and weight measurements cannot be made.

Defective brown adipose tissue thermogenesis in obese mice

Abstract: Defective BAT thermogenesis is associated with obesity in all the different types of obese animal so far studied. The deficit in normal energy expenditure may be presumed to contribute to the high metabolic efficiency and, together with the hyperphagia, to the obesity of these animals. In two types of obese animal (the ob/ob mouse, the db/db mouse) an increased propensity to become torpid provides an additional energy conserving mechanism that contributes to the high metabolic efficiency. In all these animals an abnormality of hypothalamic function appears likely. Obviously animals with induced hypothalamic lesions (the VMH-lesioned rat, the GTG-obese mouse) have an interruption in the normal pathway that links diet and the sympathetic innervation of BAT. The fa/fa rat resembles these animals in failing to activate BAT thermogenesis in response to diet: the lesion may lie in the hypothalamus itself or elsewhere in the food-intestine-hypothalamus-BAT axis, for example in intestinal peptide hormones. The ob/ob mouse has a peculiar hypothalamic defect that interferes with control of thermogenesis in BAT as well as impairing or exaggerating some aspects of thermoregulation. The db/db mouse resembles the ob/ob mouse but, since the defect is genetically distinct, presumably has a different lesion at the molecular level.

Adipose tissue growth patterns during human gestation: a histometric comparison of buccal and gluteal fat depots.

Abstract: Morphometric analysis of fat lobule size and number, and fat cell number in middle buccal and gluteal fat depots during the prenatal period was carried out using histological sections from 88 typical-for-age or normal human prenates of both sexes. The sample ranged from 110 to 385 mm Crown-Rump length (or from 14 through 42 gestational weeks). Compared with the buccal fat pad, the gluteal fat was one to four weeks delayed in lobule maturation. In addition to fat maturation differences between buccal and gluteal fat sites, gluteal fat characteristically showed fewer but larger fat lobules than did the buccal fat pad. Conversely there appeared a larger number of fat cells per unit area in the buccal fat than in the gluteal fat. Fat accumulation in human buccal and gluteal fat depots include differences in growth timing and magnitude, but also different developmental patterns. These patterns suggests our hypothesis that while lobule hyperplasia and hypertrophy occur at both sites, gluteal fat lobules grow primarily through lobule hypertrophy whereas the buccal fetal pad grows through lobule hyperplasia.

Therapeutic doses of phenylpropanolamine increase supine systolic blood pressure.

Abstract: Overfeeding normal volunteers with either carbohydrate or a mixture of supplements for 20 days increased resting metabolic rate, but most of the excess energy was retained. There was no significant increase in urinary VMA or catecholamine excretion or plasma catecholamine concentrations during overfeeding, suggesting that there was no diffuse activation of the sympathetic nervous system. Overfeeding did not enhance the thermogenic response to norepinephrine infusion, suggesting that the increase in resting metabolic rate during overfeeding in man is not mediated by increased sensitivity to norepinephrine or by hypertrophy of brown fat. Propranolol slightly reduced postprandial resting metabolic rate during overfeeding is not mediated by increased sympathetic nervous system activity. These data are not consistent with the hypothesis that the sympathetic nervous system regulates dietary thermogenesis in man.

Participation of alpha-adrenoreceptors in brown adipose tissue thermogenesis in vivo.

Abstract: There is evidence for involvement of gastrointestinal hormones in pathogenesis of obesity and reports on lipolytic activity in animals. The in vitro lipolytic activity of these hormones was tested in human adipocytes. Vasoactive intestinal polypeptide, glucagon, secretin, human gastrin I, gastrin releasing polypeptide, gastric inhibitory polypeptide, pancreatic polypeptide, motilin, bombesin, neurotensin, C-peptide, as well as cholecystokinin did not stimulate lipolysis significantly above basal. These results indicate that the involvement of these hormones in obesity in man might not be due to a direct lipolytic effect on the human adipocyte.

Fat cell adrenoceptors: inter- and intraspecific differences and hormone regulation.

Abstract: The present review summarizes recent data on fat cell adrenoceptors with the aim of clarifying the role played by catecholamines in the regulation of adipocyte metabolism. Part of the review is focused on the possible interest of animal models for the study of catecholamine-mediated effects in human fat cells. It is now clearly demonstrated that human, hamster, dog and rabbit fat cells possess three basic types of adrenoceptor: the beta 1-, alpha 2- and alpha 1-adrenoceptors identified in biological assays or binding studies with selected radioligands. The rat is an exception in the species commonly studied as catecholamines exert an exclusive lipolytic effect through beta-adrenoceptor stimulation, there are no alpha 2-adrenoceptors in rat white fat cells although an alpha 1-adrenoceptor does exist. In human fat cells, physiological amines are lipolytic or antilipolytic. Binding studies have revealed that alpha 2-adrenoceptors are three to four times more numerous than beta 1-adrenoceptors. Moreover physiological amines, in particular epinephrine, have a higher affinity for alpha 2-sites than for beta 1-sites. Dose-response studies of the effect of epinephrine on adenosine-deaminase or isoproterenol-stimulated fat-cells demonstrate an inhibitory effect of epinephrine on lipolysis promoted by stimulation of alpha 2-adrenoceptors which occurs before the commonly described beta 1-adrenergic effect which promotes stimulation of lipolysis. This aspect and its putative physiological interest is described and discussed. Intraspecific variations in adrenergic responses of adipocytes have been briefly analysed. The appearance and disappearance of alpha 2-adrenoceptors according to the extent of adipose tissue and increment of fat cell size are discussed. Variations of adrenergic responsiveness during fasting, calorie restriction or chronic stimulation of the adipocytes by physiological amines are also discussed.

Adipose conversion of ob17 cells and hormone-related events.

Abstract: The ob17 preadipocyte clonal line has been established from the adipocyte fraction of the epididymal fat pads of adult C57 BL/6J ob/ob mice. In vivo, injection of ouabain-resistant mutant cells (ob 17OR11 cell line) into athymic mice is followed by the formation of fat pads containing ouabain-resistant mature fat cells. In vitro, ob17 cells develop after confluence biochemical and morphological characteristics of adipocytes. The adipose conversion process is best represented by a stochastic model in which a pool of stem cells (adipoblasts) give rise to clusters of adipose cells and to additional stem cells that remain in the population. The role of the different factors involved in such conversion is discussed; (1) factors that enhance the number of susceptible cells (ACF or ACF-like compounds), (2) factors without which no adipose conversion takes place (triiodothyronine, growth hormone and other factors still to be characterized), (3) factors that enhance the expression of the differentiation program (insulin). The early emergence of lipoprotein lipase occurs normally in insulin-depleted medium. The separation of ob17 cells by isopycnic centrifugation shows that lipoprotein lipase is present at high levels in early differentiating cells which are still devoid of late markers, ie glycerol-3-phosphate dehydrogenase and triglycerides. These results are discussed with respect to the determination of cellularity during development of adipose tissue in vivo.

Increased metabolic efficiency in obese mutant mice.

Abstract: Body composition (percent fat and lean body mass) and basal metabolic rates were determined in 67 obese adolescents ranging in age from 10 to 16 years (30 male, 37 female). Basal oxygen uptake was determined on rising in the morning using open-circuit spirometry with a 10-min collection period. Body composition was determined from body density measurements using the underwater weighing procedure. There were no male-female differences (except for basal VCO2 production, P less than 0.05) for any body composition or metabolic variable. The subjects' (male and female) average weight was 73 kg, height--157 cm, percent fat--40 percent, fat weight--30 kg, lean body mass--92 kg, and kcal/24 h--1535. Correlations between age, body composition and basal energy expenditure were all moderate to low (r less than or equal to 0.78). In contrast to adult data, lean body mass was not highly correlated to basal energy expenditure suggesting that perhaps there is a 'metabolic condition' of the obese adolescent modulated by excess fatness or the instability of the body cell mass. Stepwise multiple linear regression revealed that for the obese male adolescent, body surface area and percent fat, and for the obese female adolescent body surface area and body weight resulted in the best prediction of basal kcal/24 h. The standard errors of prediction were +/- 17.9 percent for the males, and +/- 14.4 percent for the females.