Brown (BAT) and white (WAT) adipose tissue in high-fat junk food (HFJF) and chow-fed rats with dorsomedial hypothalamic lesions (DMNL rats)

Male weanling rats received dorsomedial hypothalamic nucleus lesions (DMNL) or sham operations and were fed for 173 postoperative days a high-fat diet and given a 32% sucrose solution as drinking fluid. This was supplemented with chocolate chip cookies, potato chips and marshmallows. Other DMNL and sham-operated controls were fed lab chow instead of the above high-fat junk food diet (HFJF) and given tap water instead of 32% sucrose solution. All animals were killed on postoperative day 174. Caloric intake per 100 g body weight was similar in all groups; however, the HFJF fed control and DMNL rats had significantly elevated carcass fat. Since HFJF-DMNL rats were not nearly as obese as the HFJF control animals, it appears that the DMNL offered some protection against the HFJF-diet-produced obesity. When their smaller body size is considered. DMN lesions had no effect on brown adipose tissue (BAT) mass in chow-fed or HFJF fed rats, whereas BAT size was significantly enlarged in HFJF-fed control animals. This suggests but does not prove that HFJF-fed controls, but not DMNL rats, may be using dietary-induced thermogenesis (DIT) to attenuate their obesity. We hypothesize that the HFJF-fed DMNL may not be enhancing DIT as reflected in normal BAT size, because they had not attained a degree of fatness to activate this system, or the DMN lesions impaired its activation. Both HFJF-fed groups showed reduced linear growth compared to their counterparts. The reason for stunting is uncertain, but may be related to their low plasma insulin concentrations.

A comparison of measurements of lean body mass derived by bioelectrical impedance, skinfold thickness and total body potassium. A study in obese and non-obese normal subjects

The measurement of body composition is an important part of metabolic and epidemiological research, but most currently available methods are complex and expensive. We have, therefore, compared measurements of fat mass (FM) and lean body mass (LBM), obtained using a commercially available bioelectrical impedance monitor (The Holtain Body Composition Monitor) (IMP), and by measuring skinfold thickness (SFT), with values obtained by measuring total body potassium (TBK). Twenty subjects, 10 with a body mass index (BMI) less than 30 (kg m-2), (non-obese) and 10 with BMI greater than or equal to 30 (obese) took part in the study. There was a strongly significant linear relationship between LBM calculated from TBK and that calculated from impedance (IMP), in both non-obese and obese groups analysed separately (non-obese: r = 0.92; p less than 0.001 and obese: r = 0.92; p less than 0.001) and together (all: r = 0.89; p less than 0.001). LBM calculated from TBK was strongly linearly correlated with values derived from SFT for non-obese (r = 0.91; p less than 0.001) but not for obese subjects. Mean values of LBM of non-obese subjects derived by each method were not significantly different (TBK: 51.3 +/- 10.40 kg; IMP: 53.18 +/- 10.37 kg; SFT: 48.87 +/- 9.48 kg), but significant differences existed when the subjects were obese (TBK: 51.86 +/- 9.65 kg; IMP: 58.69 +/- 8.55 kg; SFT: 67.61 +/- 8.14 kg; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in body composition and energy expenditure after six weeks' growth hormone treatment

Changes in body composition and energy expenditure were assessed in 15 children after six weeks of human growth hormone (hGH) treatment. Body composition measurements were made by stable isotope labelled water (H2(18)O) dilution, bioelectrical impedance, and skinfold thickness techniques. Energy expenditure was assessed both by indirect ventilated hood calorimetry (resting energy expenditure) and the stable isotope doubly labelled water (2H2(18)O) technique (free living daily total energy expenditure). Mean increases in weight of 0.96 kg and fat free mass of 1.37 kg and a mean decrease in fat mass of 0.41 kg were observed. Significant increases both in resting energy expenditure and free living daily energy expenditure were detected. Absolute changes in fat mass and resting energy expenditure were correlated. The data suggest (i) that the increase in the fat free mass is the most significant early clinical measure of hGH response and (ii) that hGH increases the metabolic activity of the fat free mass. Monitoring such changes may be predictive of the efficacy of hGH in promoting growth.

Effect of cholecystokinin immunization, enhanced food intake and growth of swine on lean yield and carcass composition

It was previously reported that cholecystokinin (CCK) immunization of swine increased food intake 8.2% and rate of growth 10.6%. This report compares carcass yields of lean, fat and bone tissues of CCK-immunized vs. human serum globulin (hSG) control animals. The experiment involved 24 castrated pigs, age 75 d, weight 25.6 kg, randomly assigned to the CCK-immunized or hSG control groups (2 pigs/pen, 6 pens/group). Food was offered for ad libitum access. Carcasses of CCK-immunized animals (vs. hSG controls) were 8.7% heavier (P less than 0.01) and 2.4% longer (P less than 0.01). Carcass yield and composition were analyzed by dissection to lean, fat and bone fractions and by proximate analysis of the resultant lean fraction. Carcasses from the CCK-immunized animals had 2.7 kg more lean (P = 0.09) and 1.8 kg more fat (P = 0.04). Proximate analysis indicated there were no significant differences in composition of the lean fraction. The 7.2% heavier lean fractions of the CCK-immunized animals contained 9.2% more protein (P = 0.09) and 5.1% more fat (P = 0.05). Lean:fat and protein:fat ratios were not significantly altered.

Effects of diabetes and insulin on photoperiodic responses in Siberian hamsters

Short day pineal melatonin secretion patterns cause gonadal regression in Siberian hamsters, an effect due to alterations in gonadotropin secretion that ultimately affects the gonads. An analogous endocrine response sequence may underlie short day (melatonin)-induced decrease in body weight (fat) in this species. A potential mediating hormone for this effect of melatonin may be insulin. The purpose of the present experiments was to determine whether alterations in insulin status might affect the photoperiodic control of body weight (fat) and reproductive condition. Insulin was controlled by inducing experimental diabetes mellitus via injections of streptozotocin across several days, followed by treatment with one of two doses of long-lasting insulin. Both insulin doses normalized urinary glucose, but not body weight in long days. Seven weeks of short day exposure caused gonadal regression in all groups regardless of insulin status. The magnitude of the short day-induced decrease in body weight and carcass lipid was directly related to long day baseline body weights; however, the body weight nadir reached was similar among the groups. A 'regulation' of seasonally appropriate body weight (fat) is implied by these findings.

Body mass index as a measure of body fatness: age- and sex-specific prediction formulas

In 1229 subjects, 521 males and 708 females, with a wide range in body mass index (BMI; 13.9-40.9 kg/m2), and an age range of 7-83 years, body composition was determined by densitometry and anthropometry. The relationship between densitometrically-determined body fat percentage (BF%) and BMI, taking age and sex (males = 1, females = 0) into account, was analysed. For children aged 15 years and younger, the relationship differed from that in adults, due to the height-related increase in BMI in children. In children the BF% could be predicted by the formula BF% = 1.51 x BMI-0.70 x age - 3.6 x sex + 1.4 (R2 0.38, SE of estimate (SEE) 4.4% BF%). In adults the prediction formula was: BF% = 1.20 x BMI + 0.23 x age - 10.8 x sex - 5.4 (R2 0.79, SEE = 4.1% BF%). Internal and external cross-validation of the prediction formulas showed that they gave valid estimates of body fat in males and females at all ages. In obese subjects however, the prediction formulas slightly overestimated the BF%. The prediction error is comparable to the prediction error obtained with other methods of estimating BF%, such as skinfold thickness measurements or bioelectrical impedance.

Haemodynamic, metabolic and endocrine effects of short-term dexfenfluramine treatment in young, obese women

Seventeen normotensive, premenopausal women were treated with the 5-hydroxytryptamine-reuptake inhibitor dexfenfluramine 30 mg per day, for 4 days in a randomised double-blind, cross-over, placebo controlled trial. Energy intake was held constant during the study as the aim was to study the endocrine and metabolic effects of dexfenfluramine dissociated from its weight-lowering properties. Body weight, blood glucose, plasma insulin, cholesterol triglycerides and C-peptide after an overnight fast and during an oral load of 100 g glucose did not change after dexfenfluramine compared to placebo. Supine and standing systolic and diastolic blood pressures were significantly decreased, while heart rate remained unchanged. Plasma noradrenaline and plasma renin were markedly reduced by dexfenfluramine, and cortisol, beta-endorphin and thyroid hormones were not changed. Thus, dexfenfluramine has a significant hypotensive effect in normotensive, obese women after 4 days of treatment, independent of a negative energy balance. This was associated with decreased circulating plasma noradrenaline, indicating decreased sympathetic nerve activity. Dexfenfluramine may be a candidate drug for longer-term trials in the treatment of primary hypertension associated with obesity.

Assessment of abdominal fat deposition in female cynomolgus monkeys

Computed tomography (CT) was used to assess abdominal fat distribution in adult, female cynomolgus macaques (Macaca fascicularis). The technique used was similar to that applied in human beings and allowed intra-abdominal, subcutaneous and total abdominal fat to be quantitated in 1 cm thick sections. Correlations between single scans and the average of scans at several levels ranged from r = 0.96 to r = 1.00, indicating that a single scan is representative of abdominal fat distribution. Significant positive correlations were found between body mass index (BMI) and intra-abdominal fat (r = 0.89), subcutaneous fat (r = 0.91) and total abdominal fat (r = 0.90). As BMI increased, fat was preferentially deposited subcutaneously versus intra-abdominally. A unique fat depot, not previously described, was identified dorso-laterally between the internal abdominal oblique and the transversalis muscle. This fat depot was also positively correlated with BMI (r = 0.79). These results indicate that CT can be used in cynomolgus monkeys to quantitate regional fat deposits and that these monkeys resemble human beings in their abdominal fat patterning.

Exercise and body composition

We assessed changes in body composition in 41 young adults who engaged in various exercise and/or training programs on ad libitum diets. Most of those who gained weight sustained an increase in lean body mass (LBM), and most of those who lost weight lost LBM as well as fat. The change in LBM was directly related to the change in weight, with a regression slope of 0.500. An analysis of published data confirms these findings and, in concert with our data, provides the additional information that the magnitude of the change in body composition in exercising individuals is influenced by body fat content, just as it is for nonexercising individuals.

Body fat in lean and overweight women estimated by six methods

Body fat content of seven lean women (body mass index (BMI) 20.6 (SD 1.8) kg/m2) and seven overweight women (BMI 31.1 (SD 3.3) kg/m2) was estimated by six different methods: underwater weighing (UWW), body-water dilution (BWD), whole-body counting (40K), skinfold thickness (SFT), bioelectrical impedance (BEI) and magnetic resonance imaging (MRI). Using UWW as the reference method, the differences between percentage fat by each other method and the percentage fat by UWW were calculated for each subject. The mean difference was lowest for SFT and highest for BWD. MRI showed the lowest variability in individual results, and 40K the highest. 40K and BWD methods used in combination gave better agreement with UWW results than either 40K or BWD methods alone. There was a weak negative correlation between the difference from the UWW results and percentage fat in the SFT measurements, but not in the BWD, 40K, BEI or MRI measurements, suggesting that for these methods the assumptions involved produced no greater inaccuracy in the overweight women than in the lean women. In all subjects the BEI offered little improvement over the traditional SFT measurements. The agreement between MRI and UWW estimates in both lean and overweight women suggests that MRI may be a satisfactory substitute for the more established methods of body fat estimation in adult women.

An evaluation of waist to hip ratio measurement methods in relation to lipid and carbohydrate metabolism in men

The purpose of this study was to determine which method of measuring waist to hip ratio (WHR) was the most effective in assessing decrements associated with an abdominal fat distribution in 46 non-obese, middle to older aged men (mean +/- s.e., age 52.8 +/- 0.88 years; body fat 19.7 +/- 0.72 percent). Circumferences were obtained at the following sites and WHR calculated (waist circumference/hip circumference): (1) minimal waist/maximal hip; (2) level of umbilicus/maximal hip; (3) level of umbilicus/level of greater trochanters; (4) level of umbilicus/level of superior iliac spine; and (5) level of 1/3 of the distance between the xiphiod process and umbilicus/level 4 cm below the superior iliac spine. Significant (P less than 0.05) associations were observed for measurement methods 1, 2 and 3 with indices of lipid and carbohydrate metabolism, body composition, and fitness level. Measurement method 5 was not related to any metabolic or physiological variables, while measurement method 4 was intermediate in terms of the strength of the associations. These findings suggest that the predictive strength of WHR can vary depending upon the measurement method used.

High sucrose diet increases visceral fat accumulation in VMH-lesioned obese rats

We have previously reported that metabolic abnormalities in obese subjects are closely related to intraabdominal fat accumulation. In order to clarify the causal relationship between high sucrose intake and intraabdominal visceral fat accumulation, the effects of a high sucrose diet on mesenteric fat weight, fasting plasma glucose (FPG) and triglyceride (TG) levels were investigated in bilateral ventromedial hypothalamic-lesioned obese rats (VMH) and control rats (control). The mesenteric fat weight (g)/abdominal subcutaneous fat weight (g) (M/S ratio), a parameter of visceral fat accumulation, was significantly higher in a high sucrose diet fed group (HSD group) (VMH 1.94 +/- 0.71, control 1.63 +/- 0.28) than in a lab chow fed group (LC group) (VMH 1.30 +/- 0.31, control 1.27 +/- 0.33) (P less than 0.01). In addition, the fat cell volume of mesenteric fat deposits was significantly greater in the HSD group (VMH 1.17 +/- 0.26 nl, control 0.24 +/- 0.10 nl) than in the LC group (VMH 0.74 +/- 0.27 nl, control 0.14 +/- 0.07 nl) (P less than 0.001), although the fat cell number did not differ among any experimental rat groups. FPG and TG levels were higher in the HSD group than in the LC group in VMH-lesioned rats, and a significant correlation was observed between mesenteric fat volume and FPG levels (VMH r = 0.58, P less than 0.05; control r = 0.50, P less than 0.05) as well as between mesenteric fat volume and TG levels (VMH r = 0.49, P less than 0.05; control r = 0.56, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of exercise on energy balance in meal-fed mice

The effects of exercise on energy balance have been investigated in mice accustomed to eating their daily food ration in three meals. A meal period lasts 1 hour, and during that period mice were allowed to eat unrestrictedly a pelleted stock diet. Two series of experiments were conducted. In one series of experiments indirect calorimetric measurements were carried out in untrained mice that were assigned to 3 experimental groups; a first group of mice was allowed to rest; a second group of mice was exercised immediately before one of the 3 meals; a third group of mice was exercised immediately after one of the 3 meals. The exercise bout consisted of 1 hour of forced exercise on a rodent treadmill at a speed of 20 meters per minute. O2 consumption (VO2) and CO2 production were monitored throughout a full day except at the time the exercising animals were on the treadmill. In a second series of experiments long-term energy balance measurements were carried out. Mice were then assigned to experimental conditions similar to those previously described for 31 days during which period food intake and body weight were continuously monitored. At the end of 31 days of experiment, mice were killed, and their carcasses were individually analysed for their contents of energy, fat and protein. Carcass and food gross energy contents were assessed by bomb calorimetry. At the end of the long-term energy balance trial, the percentage of fat, the energy gain, the energy density and the weight of the dry carcass were significantly lower in exercised groups of mice than in the resting group of animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of nutrition and bovine growth hormone (GH) on hepatic GH binding, insulin-like growth factor-I and growth of lambs

The effect on young lambs of 0.25 mg recombinant bovine GH (bGH)/kg per day on plasma concentrations of insulin-like growth factor-I (IGF-I), glucose, specific hepatic GH binding and body composition changes was examined at two levels of nutrition (lucerne pellets; 3 and 1.7% of body weight/day). Lambs on low levels of nutrition had low plasma IGF-I (P less than 0.001). Plasma concentrations of IGF-I were increased by bGH treatment at both levels of nutrition, with the high nutrition group showing the greatest IGF-I response after 3 and 40 days of bGH treatment. Plasma glucose, after 40 days, was higher overall (P less than 0.05) in lambs on high nutrition. bGH treatment increased plasma glucose, with the response being greater in the well-fed lambs. Specific binding of GH to liver membranes was highest in lambs on high nutrition and on bGH treatment; no significant interaction between nutrition and bGH treatment was detected, indicating that specific binding of GH was increased proportionally by bGH at both nutritional levels. The major change in body composition was the reduced level of fatness in lambs treated with bGH. There was no significant effect of bGH on body weight although bGH treatment tended to increase weight gain of well-fed lambs and decreased weight loss of poorly nourished lambs. The results show that, although there was a significant (P less than 0.05) bGH/nutrition interaction for IGF-I there was no such interaction for body weight/components or specific GH binding to the liver. The results indicate that an increase in plasma IGF-I does not necessarily result in increases in growth or changes in carcass composition.

Suppression of natural killer cell activity by ethanol consumption and food restriction

Effects of 4-week food restriction and ethanol consumption on natural killer (NK) cell activity and carcass composition were evaluated. Female, C57BL/6 mice given water (H2O) or ethanol (20% w/v, ETOH) ad libitum were placed in one of three dietary groups: unrestricted (UNR), moderately restricted (MR, 2.2 g/day), or severely restricted (SR, 1.8 g/day). Food restriction alone (MR, SR) significantly reduced body, spleen, and thymus weights; carcass lipid content (SR only); spleen cell number; and baseline and interleukin-2 (rIL-2) stimulated NK cell activities. Ethanol consumption was unaffected by food restriction and in restricted mice it did not suppress food intake. Thus, average calories derived from ethanol increased from 30% (UNR) to 40% (SR) with the degree of food restriction in these groups. Mice given ethanol and restricted food intake had at least as heavy or heavier body, spleen, and thymus weights than water-drinking (H2O) counterparts. Spleen cell number was reduced in ethanol-consuming (ETOH), food restricted groups compared with UNR H2O control. Baseline NK cell activity was suppressed 50% to 90% in all ETOH and food-restricted groups. rIL-2 stimulated NK cell activity was suppressed 18% to 76% in food restricted mice independent of ethanol intake. These results indicate that supplementary ethanol calories did not enhance NK cell activity in UNR ETOH mice, nor did they protect splenic NK cell activity from the suppressant effects of food restriction. Ethanol consumption significantly increased carcass lipid content in all groups compared with their H2O counterparts. This increase was largely responsible for the preservation of body weight in ETOH mice especially during food restriction.

Lean tissue mass is a useful predictor of induction dose requirements for propofol

The effect of age and sex on ED50 values for propofol was studied in 92 patients aged between 16 and 85 years. All doses were based on lean tissue mass (LTM). The end-point for loss of consciousness was loss of the ability to hold a light object. The mean of the ED50 values for males was 1.31 mg.kg LTM-1 and for females 1.28 mg.kg LTM-1. For males the ED50 values ranged from 0.94 to 1.69 mg.kg LTM-1. For females, the range was 1.06-1.57 mg.kg LTM-1. On statistical analysis, these differences were not significant. These data contrast with other studies in which dosage was based on total body mass where a decrease in dose requirement with age was demonstrated. We propose that by using lean tissue mass to calculate dosage, considerable normalisation of patient response can be achieved. There is considerable inter-individual variation in response to propofol. Age is less important than this variation in determining the correct dose for each patient, provided doses are based on LTM.

Biochemical cost of a fight in fed and fasted Betta splendens

Behavioral and biochemical effects of threat displays and fights were determined in both fed and fasted animals. A week-long fast resulted in subtle behavioral modifications and a significant reduction in muscle glycogen. Threat displays had no effect on carcass composition. In the course of fighting, fed animals degraded large amounts of lipids, glycogen and amino acids, while fasted animals degraded only glycogen. Two alternative hypotheses are proposed to explain the difference between the biochemical effects of a fight in fed and starved animals.

Body composition and sleeping metabolic rate in response to a 5-month endurance-training programme in adults

This study examined the effect of exercise training on body composition and sleeping metabolic rate (SMR) in 15 men and 13 women who participated in a 20-week training programme aimed at running a half marathon. Body mass (BM) was measured after waking up, fasted and with an empty bladder. Body composition was assessed using densitometry. The SMR was measured from 0300-0600 hours during an overnight sleep in a respiration chamber. Assessment of SMR was at least 36 h after the last period of exercise training. After 20 weeks of endurance training no change in BM was observed. However, body composition changed significantly. On average men lost 2.4 kg body fat (P less than 0.01) and gained 1.7 kg fat free mass (FFM) (P less than 0.01). In women fat loss averaged 0.9 kg after 20 weeks (P less than 0.01), while FFM increased by 1.0 kg (P less than 0.05). Loss of fat mass was significantly larger in males (P less than 0.05). No changes in SMR were found, either in absolute terms, or when normalised for BM or FFM. Therefore, we have concluded that exercise training has no chronic, long-term effect on SMR. A possible explanation for this outcome in view of the different findings in similar studies is discussed.

Effects of ambient temperature and body fat content on maternal litter reduction in Syrian hamsters

Reproduction in Syrian hamsters is sensitive to the general availability of metabolic energy. For example, females often modify their litter size by cannibalism on days 1-7 postpartum, and the number of young eaten is a function of the total supply of metabolic energy as determined by both food supply and body fat content. If the level of cannibalism is a function of energy availability, it might be expected that a drop in ambient temperature would increase cannibalism, since cold acclimation demands greater energy expenditure. We found that hamsters ate significantly more of their offspring when housed at 10 compared to 22 degrees C during lactation. The effect of cold on cannibalism was attenuated in hamsters fattened prior to cold exposure and exaggerated in hamsters that were lean prior to cold exposure. Thus, the litter size maintained by Syrian hamsters is a function of the total supply of metabolic fuels as determined by energy sources, such as food supply and adipose tissue, and by energetic costs of thermoregulatory and other processes.

Body composition in hypertensive elderly and middle-aged patients

The occurrence of hypertension, leading to various life-threatening complications in the elderly is a widely recognized problem. The changes of body composition were determined in 120 control and untreated hypertensive subjects of various ages. In middle-aged hypertensive males, the total blood volume and plasma volume increased significantly compared to those of the healthy controls, while this increase was not significant in the case of hypertensive middle-aged females. In contrast, in the elderly hypertensive male subjects, the volume of all fluid components decreased, except the total body fat and the vascular volumes. There was a slight, statistically non-significant, increase in all the vascular volumes except in the red cell mass. The elderly hypertensive females showed the same tendency compared to the healthy controls of the same age. The vascular compartments seem to be decreased in elderly males, compared to those of the middle-aged males, while slightly increased in elderly females.

Perioperative monitoring of total body water by bio-electrical impedance in children undergoing open heart surgery

Knowledge of the changes in total body water (TBW) following cardiac surgery (OHS) in children would be of value in fluid therapy and in researching the causes and management of capillary leak. We have validated a bioelectrical impedance technique (BEI) for non-invasive estimation of TBW in children after OHS. We report the use of this method in a longitudinal study. Twenty patients (mean age 4.7 years +/- 3.5 (SD), mean weight (WT) 16.2 kg +/- 1 kg) undergoing a variety of complex OHS procedures were studied from 1 day preoperatively to 4 days postoperatively. Anaesthetic and basic bypass (CPB) techniques were uniform. Six patients underwent CPB at less than 20 degrees C, 10 at 20 degrees - 25 degrees C and 4 at 26 degrees - 33 degrees C. TBW (BEI), core (ctemp) and peripheral (ptemp) temperatures and fluid balance (TFB) were recorded at frequent intervals. TBW (by BEI) rose (P less than 0.001) following CPB in all patients from 62% +/- 9% (SD) body weight preoperatively to 73% +/- 13% in the ICU (an increase of 11% +/- 5%). TBW remained significantly elevated until the 3rd postoperative day. Multivariate analysis (MVA) confirmed that TBW was significantly related to TFB, but not to ctemp or ptemp. MVA also revealed smaller patient size (height and weight), younger age and longer CPB time as incremental risk factors for the rise in TBW.

CONCLUSIONS

(1) BEI permits the non-invasive study of TBW in children after OHS, when TBW variation may be considerable. (2) The smaller the child and the longer the CPB, the greater the rise in TBW. (3) The technique should be a valuable tool in researching the major water fluxes associated with CPB in children.

[Effect of sports on the distribution of body fat]

The pathogenetic effectiveness of the risk factor overweight is essentially modified by the distribution of the fatty depot. The form of obesity, the primary obesity, which above all is to be found in men is connected with a relatively high risk for the appearance and progression of several chronic diseases which at present determine morbidity. An only two-hour sports activity per week has a great influence on the size and the distribution of the lipopexia. Sporting persons have less body fat than inactive ones. In particular in sporting males the deposition of fat in the abdominal region is much limited.

Diet composition determines course of hyperphagia in developing Zucker obese rats

Previous observations from this laboratory indicate that, during growth, the hyperphagia of the male genetically obese Zucker rat reaches a peak or "breakpoint" and then declines. To examine the effect of dietary macronutrient content on the course of hyperphagia, groups of male lean and obese rats were maintained from 5-28 weeks of age on powdered chow, or isocaloric diets (3.6 kcal/g) containing 72% of calories as corn oil, dextrose, or soy isolate protein (n = 5 lean and obese rats/diet). On chow, hyperphagia was maintained at a level of 7-8 g above lean control intake until a "breakpoint" was reached at 17 weeks, and obese intake declined to lean control level. On the fat diet, hyperphagia was increased to 10 g/day when a breakpoint was reached at 8 weeks. On the dextrose and protein diets, hyperphagia at a level of 3-4 g/day reached breakpoints at weeks 18 and 16, respectively. On all diets, the intakes of obese rats were precisely equal to the intakes of lean control rats by weeks 19-20. These data show that the magnitude and duration of hyperphagia in the developing obese rat are influenced by diet composition. Previously, we have proposed that the obese rat's hyperphagia arises from rapid adipocyte filling. Since high-fat diets facilitate adipocyte enlargement, the early "breakpoint" of hyperphagia seen with the high-fat diet may indicate that this feeding stimulation decreases as the fat cells of the obese rat approach maximal size.

Body composition alterations consequent to an exercise program for pre and postmenopausal women

The purposes of this study were: (a) to evaluate the effects of an exercise program upon the body composition of premenopausal (no. 43) and postmenopausal (no. 66) women, aged 35-70 years, and (b) to compare exercise Ss with age matched control Ss. Body composition was assessed by skinfold measurement and hydrostatic weighing. Exercise Ss walked or jogged and performed light resistive exercise for 60 minutes per day three times per week for 24 weeks. Control Ss remained sedentary. ANOVAs revealed: (a) no significant (p greater than or equal to .05) differences in exercise training effects between premenopausal and postmenopausal Ss, and (b) exercise Ss exhibited less body fatness while control Ss possessed more body fat as represented by significant changes (p less than or equal to .05) for the exercise and control Ss, respectively in: body density (+.002 g/cc, -.001 g/cc); % fat (-1.2%, +.6%); fat weight (-.4 kg, +1.1 kg); suprailiac skinfold (-.3 mm, +7 mm); and abdominal skinfold (-.3 mm, +1.5 mm). It was concluded that: (a) menopausal status did not alter the effects of exercise in this study, and (b) exercise training produced a positive effect in the exercise Ss by reversing body composition trends associated with a sedentary lifestyle.

A physiological comparison of female body builders and power lifters

Ten female body builders (FBB) (X age +/- SD = 30.40 +/- 8.22 years) and ten female power lifters (FPL) (X age +/- SD = 25.20 +/- 6.01 years) were studied to determine group differences in body composition, strength and anaerobic characteristics. All subjects had been training a minimum of two years and twelve of the subjects had competed nationally while the remainder had participated in regional or local events. Measures of body build and body composition were obtained via hydrostatic weighing, skinfolds (sum of 7), circumferences (sum of 13) and diameters (sum of 9). Flexion and extension strength of the dominant forearm and leg were measured with a Cybex II dynamometer at 60 degrees/second. Anaerobic power and capacity were determined using the Wingate Anaerobic Test. Independent t-tests indicated the FPL had significantly greater body weight (X +/- SD = 68.60 +/- 3.60 vs 56.47 +/- 0.85 kg), relative fat (21.47 +/- 1.29 vs 13.51 +/- 1.46%), sum of skinfolds (120.76 +/- 7.55 vs 71.46 +/- 7.02 mm), sum of diameters (177.57 +/- 2.97 vs 168.17 +/- 2.55 cm), and sum of circumferences (594.93 +/- 13.10 vs 551.24 +/- 3.17). No significant differences were found for fat-free weight, strength or anaerobic power and capacity. These results demonstrate subtle but specific differences between well-trained FBB and FPL reflecting the leaner physiques and smaller skeletal structures of the FBB necessary for the definition and symmetry demanded by the sport. The lack of differences in strength and anaerobic characteristics reflect the similarity of the groups in basic training techniques.

Somatic, endocrine and metabolic changes in controls pair-fed for six weeks to rats with dorsomedial hypothalamic nucleus lesions (DMNL rats)

One group of weanling male Sprague-Dawley rats received lesions in the dorsomedial hypothalamic nuclei (DMNL rats), whereas two additional groups of rats were sham-operated (CON). One of these CON groups was allowed to feed ad lib (CON-ADLIB) while the other CON group was pair-fed for 6 weeks to the DMNL rats (CON-PF). Despite eating the same amount of food as DMNL rats. CON-PF animals had consistently lower body weights and also utilized food energy more poorly than DMNL rats. The CON-PF group also had smaller kidneys and less percent liver protein but more epididymal fat pad percent protein than DMNL rats. Whereas plasma glucose concentrations were comparable among the three groups, insulin levels were significantly higher, and free fatty acid levels lower in CON-PF than in DMNL rats. The CON-PF group incorporated less glucose-U-C14 carbon into liver glycogen but more of the tracer into liver lipid than the DMNL group. Glucose carbon was also incorporated more avidly into epididymal fat pad lipid by CON-PF than by DMNL rats. The data not only confirm previous findings in DMNL rats but in addition show that the neurologically intact rats fed the same amount of food that is eaten spontaneously by DMNL rats show somatic and metabolic alterations that suggest that they cannot cope with this low amount of substrate. The normalcy of the DMNL rats, compared to ad lib-fed sham-operated controls, in all metabolic parameters suggests that the low food intake is indeed "normal" for this preparation and may be the reflection of an "organismic" set point.

Ovariectomy accelerates the growth of microscopic hepatocellular neoplasms in the mouse: possible association with whole body growth and fat deposition

Ovariectomy (ovex) shortens the latency for development of hepatocellular neoplasms in mice, but the mechanism by which this occurs is not known. In the present study, B6C3F1 mice were given single i.p. injections of diethylnitrosamine (5 mg/kg) when they were 15 days old and either ovexed or sham operated 7 weeks later. Groups of 6 to 8 mice were killed after an additional 8, 14, 20, and 26 weeks. Four ovexed and four sham-operated mice were also killed after 56 weeks. By 8 weeks after surgery, the fractional volume of microscopic liver neoplasms in the ovexed mice was 4.3 times greater than in the shams and ablation had caused a 27% greater gain in body weight. During the following 18 weeks, tumor burdens were 3.9 to 10.6 times greater in ovexed than in the sham-operated mice and the rates of weight gain were similar in the two groups. Stereological analysis indicated that ovexed animals had more tumors than sham-operated animals, 575 versus 234/liver at 8 weeks and 952 versus 724/liver at 14 weeks after surgery. The ovex-induced increase in the number of neoplasms was spread throughout most of the size classes at both times; however, the impact on tumor burden of a small number of large tumors was only apparent at 14 weeks, when 8% of them accounted for more than two thirds of the aggregate tumor volume. The effect of the early emergence of these more rapidly growing tumors was also obvious at 1 year, when the livers of ovexed mice were more than twice the size of the shams (5.1 versus 1.8 g) and they contained 4 times as many tumors larger than 1 cm in diameter than the shams (2 versus 0.5/mouse). Since these very large tumors were invariably, at least partially, composed of trabecular hepatocellular carcinoma, ovariectomy appears to have also fostered tumor progression. The time course of ovex-stimulated weight gain and the manner in which it affected body composition were also analyzed. Eight days following ovex, the rate of weight gain abruptly increased. The acceleration persisted for only 14 days, after which it leveled off at body weights that were 24% higher than in sham-operated mice. The difference in weights resulted from 2.5 times more fat and 10% more protein in the carcasses of ovexed than sham-operated mice. This study identifies an early 8-week period in which hormonal changes resulting from ovex maximally stimulate the growth of liver tumors.(ABSTRACT TRUNCATED AT 400 WORDS)

Energy and nitrogen intake, expenditure and retention at 20 degrees in growing fowl given diets with a wide range of energy and protein contents

Heat production (HP) and the intake and retention of energy and nitrogen were measured at 20 degrees in growing female broiler fowl given diets with metabolizable energy (ME) contents ranging from 8 to 15 MJ/kg at each of two crude protein (nitrogen x 6.25; CP) contents (130 and 210 g/kg). ME intake was partially controlled by the birds, but increased by 30% over the range of dietary ME concentration. CP intake varied directly with dietary CP: ME ratio, indicating that control of energy intake took priority and that food intake did not increase in order to enhance amino acid intake on low-CP diets. Maintenance energy requirement and fasting HP were not affected by diet. Although the HP of fed birds was significantly affected by dietary energy source, there was no evidence for regulatory diet-induced thermogenesis as energy intake increased. Total energy retention doubled on the higher-energy diets as a result of increased intake and retention efficiency in the absence of any compensation by diet-induced thermogenesis. The proportion of energy retained as fat was negatively correlated with dietary CP: ME ratio. It was concluded that the growing female broiler fowl responded to large differences in energy intake and dietary CP concentration not by changes in rate of energy dissipation as heat but by changes in the quantity of energy retained and in the partition of retained energy between body protein and body fat.

Body-composition assessment using underwater weighing techniques

Health care professionals recommend that assessment of body composition be included as a part of an adult fitness program. Underwater weighing, based on Archimedes' principle, is the most valid technique for assessment of percentage of body fat and lean tissue in a clinical setting. This article presents a computer program written in BASIC that performs all of the decision-making calculations and provides the user with a tabular and a graphical summary of current body composition in addition to recommendations for changes in body composition that will enhance the subject's health.

Effect of extracorporeal membrane oxygenation on body water content and distribution in lambs

Water content of the various body compartments were estimated immediately after beginning extracorporeal membrane oxygenation (ECMO), and daily thereafter for 3 days, in seven healthy 2-month-old lambs. Total body water, extracellular water, and plasma volume were estimated simultaneously by 18O, bromide, and T-1824 dilution, respectively. Volumes of intracellular water, interstitial water, blood, and red cells were calculated from the experimental estimates. No statistically significant changes occurred in the water content of the various body compartments in relation to duration of ECMO. The data suggest that water retention, clinically noted in human neonates treated with ECMO for persistent pulmonary hypertension, may be related to the primary disease process and/or its medical management, rather than to ECMO.

Long-term effects of physical training on aerobic capacity: controlled study of former elite athletes

We studied 15-yr changes in physical training, subcutaneous fat, and maximal oxygen consumption (VO2 max) in male former elite athletes (27 long-distance runners and 9 bobsledders) and in a control group of 23 normal men. In 1973, elite athletes all trained vigorously, whereas in 1988 there was a great interindividual variation in physical training. In the lowest tertile of runners' training activity in 1988 (n = 9), the rate of decline in VO2max during the 15 yr was 1.11 +/- 0.15 (SE) ml.kg-1.min-1.yr-1, or 16% per decade, whereas the most active quintile of runners (n = 5) tended to increase VO2max (NS). The remaining 13 runners showed a rate of decline in VO2max of 0.54 +/- 0.14 ml.kg-1.min-1.yr-1, or 7% per decade. The rates of decline were 0.22 +/- 0.12 and 0.56 +/- 0.10 ml.kg-1.min-1.yr-1, or 5 and 11% per decade, in bobsledders and controls, respectively. When normalized for lean body mass instead of body weight, VO2max showed a reduced variability in the rate of decline, with values ranging from 0.00 +/- 0.27 (most active runners) to 0.69 +/- 0.15 ml.kg lean body mass-1.min-1.yr-1 (least active runners). In multiple linear regression analysis, 15-yr changes in mileage, running pace, and truncal fat together explained 51% of variance in the 15-yr change of VO2max normalized for body weight in runners and 41% in all study men. In runners, change in truncal fat was dependent on changes in both mileage and running pace. In the presence of physical training and anthropometric variables in the regression equation, the 15-yr decrease in maximum heart rate was only modestly predictive of the change in VO2max.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose tissue determinations in cadavers--a comparison between cross-sectional planimetry and computed tomography

The adipose tissue surfaces in 11 slices (+/- 5 cm from the umbilicus) were compared in two cadavers using computed tomography (CT) versus planimetry of band-sawed slices of the corresponding sections. A very close correlation was found with partial correlations of around 0.90. Retroperitoneal fat formed a considerable proportion of the total adipose tissue surface in the slices. The results were similar whether fat was defined as -250 to -50, -190 to -30, or -140 to -40 Hounsfield units. These data indicate that CT measurements agree closely with a direct morphometric method and thus can be used as a 'gold standard' for future development. The fact that fat which is located extraperitoneally, but still intraabdominally, constitutes a significant proportion of the slice surface in the umbilical region indicates that data relating intraabdominal fat measurements to metabolic functions must be interpreted with caution.

Bioelectric impedance methods for the estimation of body composition

The present use of bioelectric impedance is based upon the greater electrolyte content and conductivity of fat-free mass (FFM). The limitation of the whole body impedance approach may be the use of S2/R as an index of the conductive volume of the body. The use of body lengths that closely resemble the actual length of the conductor rather than stature can improve predictions of FFM. Theoretically, the specific resistivity approach to bioelectric impedance also provides a means of circumventing this problem. Another alternative is the estimation of whole body composition or the composition of body segments from measurements of the lengths and resistances of the segments and the use of the phase angle of the whole body and or body segments. Possible alternative methods for the use of bioelectric impedance would be the measurement of the composition of body segments, the determination of specific resistivities so that estimates of FFM can be calculated without the need for regression equations and the determination of the use of different current frequencies in measuring body composition with bioelectric impedance.

Skeletal and body-composition effects of anorexia nervosa

Eleven female patients (aged 18-46 y) with anorexia nervosa were measured by use of dual-photon absorptiometry for 1) bone mineral content (BMC, in g) and bone mineral density (BMD, in g/cm2) of the total skeleton and its regions, 2) BMD of the lumbar spine and the proximal femur, and 3) total body soft-tissue composition. The patients weighed 44.4 kg, approximately 15 kg less than normal peers (n = 22). The fat mass (3.35 kg) and content of soft tissue (7.8%) were four and three times lower (p less than 0.001) respectively, than those in normal women (15.1 kg and 26%, respectively). The total skeleton mineral (1921 g) was approximately 25% less than that of young normal women. The BMC as a fraction of the lean tissue mass was approximately 4.9% in the patients and 5.9% in normal women. Total body and femoral BMD averaged only 10% and 13% lower than those of normal women, respectively; however, spinal BMD was particularly reduced (approximately 25%, p less than 0.001).

[Variations in body height within the course of a working day]

Variation of body height during the day has been analyzed considering the influence of various occupations (standing, sitting, mixed) on the posture. In addition to this the following variables have been recorded on the 302 individuals under study: Sex, age, working time, time of getting up in the morning, kind of occupation, physique, sporting activities in the leisure-time, presence of defects of the spinal column, possibility of changes of the carriage at the working place and extensibility of the spinal column. The statistical analysis showed that with the exception of pathological alterations of the spinal column all these variables are influencing the variation of body height during the day. It could also be shown that the extensibility of the spinal column does not vary during the day. The author is discussing also ergonomical rules concerning the organization of working places for standing and sitting occupations. Finally some recommendations for the future organization of such places are given.

Measurement of the body composition of living gray seals by hydrogen isotope dilution

The body composition of living gray seals (Halichoerus grypus) can be accurately predicted from a two-step model that involves measurement of total body water (TBW) by 2H or 3H dilution and application of predictive relationships between body components and TBW that were derived empirically by slaughter chemical analysis. TBW was overestimated by both 2HHO and 3HHO dilution; mean overestimates were 2.8 +/- 0.9% (SE) with 2H and 4.0 +/- 0.6% with 3H. The relationships for prediction of total body fat (TBF), protein (TBP), gross energy (TBGE), and ash (TBA) were as follows: %TBF = 105.1 - 1.47 (%TBW); %TBP = 0.42 (%TBW) - 4.75; TBGE (MJ) = 40.8 (mass in kg) - 48.5 (TBW in kg) - 0.4; and TBA (kg) = 0.1 - 0.008 (mass in kg) + 0.05 (TBW in kg). These relationships are applicable to gray seals of both sexes over a wide range of age and body conditions, and they predict the body composition of gray seals more accurately than the predictive equations derived from ringed seals (Pusa hispida) (Stirling et al., Can. J. Zool. 53: 1021-1027, 1975) and from the equation of Pace and Rathbun (J. Biol. Chem. 158: 685-691, 1945), which has been reported to be generally applicable to mammals.

Effect of liver denervation on compensatory changes in food intake, body composition and hepatic enzyme induction after food restriction in rats

The mechanisms involved in the recovery of body fat and liver metabolism after food restriction and refeeding are not understood. This study's aim was to determine the need for hepatic neural input for the compensatory changes in food intake, body composition and hepatic lipogenic enzymes seen upon realimentation after energy restriction. Rats underwent total surgical hepatic denervation or had sham operations. One group of sham-operated and denervated rats was fed a semipurified diet ad libitum; a second group was restricted to 40% ad libitum levels for 7 d, then given free access to food during a 2-d refeeding period. Body fat content and body fat recovery rate from below "set point" were not altered by hepatic denervation. These observations do not rule out liver involvement because blood-borne factors communicating energy status information to the central nervous system could be released from the liver. The activities of hepatic enzymes--glucose-6-phosphate dehydrogenase, malic enzyme and citrate cleavage enzyme--were stimulated at least twofold by restriction and refeeding when compared to ad libitum feeding. Hepatic denervation had no effect on basal enzyme levels in ad libitum-fed animals or on elevated enzyme activity induced by refeeding after food restriction. This study clearly demonstrates that hepatic innervation is not essential for energy balance and body composition regulation. The induction of lipogenic enzymes by food restriction and refeeding does not depend on central nervous system input to the liver.

Ethanol-induced smooth and skeletal muscle myopathy: use of animal studies

This article reviews the effects of ethanol on skeletal and smooth muscle. A brief summary of its clinical effects is provided, with a rationale for the use of suitable animal models to study ethanol-induced myotoxicity. Practical details are given for the animal feeding techniques to examine the chronic effects of ethanol toxicity. Information on acute ethanol dosage experiments are also provided. Our results have indicated that ethanol causes net loss of both skeletal and smooth muscle protein and an effect on protein synthesis and/or degradation was implicated. The theoretical and practical basis of measuring protein synthesis in intact laboratory animals is reviewed. However, there are no reliable methods for measuring rates of protein breakdown in vivo. The combined results of our studies indicated that disturbances in protein synthesis were causal mechanisms for ethanol-induced myo-dysfunction. Acute ethanol exposure was largely characterised by reductions in fractional rates of skeletal and smooth muscle contractile protein synthesis. The dominant characteristics of chronic treatments were loss of skeletal and smooth muscle proteins and RNA. Further laboratory animal studies will eventually elucidate the molecular mechanisms of these changes and provide valuable information on the regulation of protein mass.

The effects of intermittent dietary restriction on weight gain and body fat in white-footed mice, Peromyscus leucopus

The effects of repeated food restriction-refeeding cycles were investigated in second generation captive Peromyscus leucopus. Mice were maintained on 50% of their individual predetermined ad lib diet for 5 days followed by 10 days of refeeding ad lib. Cycles were repeated 3 times. When compared with controls maintained ad lib for the same time period, no significant differences in final weight or fat content were observed. Restricted-refed mice were, however, observed to both lose and regain weight at increasing rates with each subsequent cycle.

Eating problems and calorie intake levels in Swiss adolescent athletes

The purpose of this study was to investigate the incidence of eating disorders (ED), calorie intake levels and body fat measures in Swiss female athletes. Thirty athletic and 34 non-athletic adolescent Swiss females were assessed for tendencies toward eating disorders and weight preoccupation using the Eating Disorders Inventory (EDI). Calorie intakes were calculated from 7-day intake records. Body compositions were determined using skin-fold measures. The athletes were divided into two groups: Those whose activities emphasize leanness (12 gymnasts, means age = 12.5 +/- 1.1 yrs), and those whose activities do not emphasize leanness (18 swimmers, mean age = 12.8 +/- 0.9 yrs). The non-athletic school-girls (mean age = 13.4 +/- 1.2 yrs) served as controls. ANOVA indicated that the gymnasts had lower body fat levels (p less than 0.01) and consumed fewer total calories (p less than 0.05) than swimmers or controls, but all groups consumed similar calories per kg/body weight. Chi square analysis indicated that similar numbers of swimmers (11%), gymnasts (1%) and controls (6%) were exceptionally preoccupied with weight (p greater than 0.05). However, more swimmers (38%) scored high on the body dissatisfaction subscale of the EDI than the gymnasts (1%) or control (9%) (p less than 0.01). In fact, more swimmers scored high on 3 subscales of the EDI compared to the other groups (p less than 0.05). It appears that disturbances in eating behaviors are not limited to sports that emphasize leanness.

Direct measurement of abdominal fat by dual photon absorptiometry

We have assessed photon absorptiometry as a new technique for direct measurement of the abdominal fat percentage (AF%). The accuracy of the method was assessed in vitro with phantoms consisting of ox muscle, lard, and a mixture of both. The results showed good linearity (r = 0.999). The in vitro reproducibility and the in vivo reproducibility were s.d. = 2.0 and s.d. = 2.8 (AF%), respectively. The AF% was measured in 148 healthy post-menopausal women and found to correlate with other measurements of fatness, such as total body fat per cent (r = 0.82, P less than 0.001), body mass index (r = 0.79, P less than 0.001) and the ratio of waist-to-hip circumference (r = 0.59, P less than 0.001). The waist-to-hip ratio, an important predictor of cardiovascular disease, was more tightly correlated with AF% than with body mass index. We conclude that this method may be a useful new research tool for direct measurements of abdominal fat, a possible cardiovascular risk factor.

Genetic and behavioral influences on body fat distribution

Genetic and environmental influences on four measures of body fat distribution - subscapular/triceps ratio (STR), waist/hip ratio (WHR), and regression-adjusted subscapular skinfold and waist circumference indices - were examined in 265 pairs of white male twins, ages 59 to 70 years, who participated in the third examination of the National Heart, Lung, and Blood Institute's Twin Study. Skinfold indices of fat distribution were not highly correlated with indices based on body circumferences (r = 0.26-0.37 for the four possible correlations). After adjustment for overall obesity, the heritability of the adjusted subscapular skinfold index was substantial (h2 = 0.60, P less than 0.001), as were estimates for both subscapular and tricep skinfolds individually. By contrast, heritability of the STR was low and of borderline statistical significance (h2 = 0.24, P = 0.06). Heritability for the WHR (h2 = 0.31, P = 0.07) was also low. Although higher estimates were observed for the adjusted waist circumference index (h2 = 0.46, P = 0.02) and for the component circumferences, these were not clearly due to genetic influences. Among behavioral influences, cigarette smoking was strongly related to the WHR and adjusted waist circumference index (P less than 0.0001). A crude measure of total physical activity was weakly, inversely related to WHR (P = 0.06), and slightly more strongly related to the adjusted waist circumference index (P = 0.01). Skinfold indices were unrelated to either behavior. We conclude that: (1) skinfold indices measure a different dimension of fat distribution than circumference indices; (2) there is evidence for a genetic influence on subcutaneous fat distribution, but less evidence for such an influence on the WHR; (3) behavioral factors appear to be more important in determining the WHR than subcutaneous fat patterning.

[Sex-specific changes in body composition during weight reduction]

The aim of this study was to ascertain whether overweight men and women of comparable age, body surface area and weight would display any differences in weight loss or changes in body composition while receiving identical calorie intakes. 15 men and 15 women of mean age 46.7 (26-57) years with obesity (body mass index 29-36 kg/m2) were given a reducing diet containing 700 kcal/d for 4 weeks. The two groups were identical in age, body weight and height. The change in body composition was studied by means of ultrasound and nitrogen balance. The women had thicker layers of subcutaneous fat (241 +/- 8 mm) over all parts of the body than the men (137 +/- 10 mm) (summated measurements at 14 points). Among the men body weight fell from 93.1 +/- 2.1 to 83.8 +/- 2.0 kg, but the women declined only from 92.9 +/- 2.0 to 84.7 +/- 1.9 kg. Although men achieved a greater weight loss (13%; P less than 0.001) the decrease in their subcutaneous fat layer was 33% less (to 117 +/- 9 mm) than in the women (211 +/- 8 mm). Cumulative nitrogen balance among the men was 4.7 times more negative than in women (-104 +/- 14 g versus -22 +/- 11 g); this points to accentuated muscle breakdown. More fat was mobilized in the women than in the men, chiefly from the regions of the limbs and hips.

Maternal hormone manipulations and the development of obesity in rats

Pregnant rats were injected with either insulin, corticosterone, thyroxin, or saline during the third trimester (week) of pregnancy. Offspring from these groups had equivalent body weights at birth and at weaning. However, beginning at approximately seven weeks of age, male offspring in the insulin condition gained weight at significantly higher rates than their counterparts in the other three conditions. This increase in body weight was accompanied by a significant increase in carcass lipid content. These effects were not observed in female offspring.

Dietary hyperphagia in rats: role of fat, carbohydrate, and energy content

Dietary energy, fat and carbohydrate content were varied to determine the nutritional factors responsible for hyperphagia induced by feeding rats high-fat diets. In the first experiment, rats were fed isoenergetic high-fat or high-carbohydrate diets for 2 weeks. Weight gain and energy intake were lower in rats given the high-fat diet. When some of the rats were switched to a diet that was high in fat, carbohydrate and energy, gram food intake was initially unchanged, resulting in a substantial increase in energy intake and weight gain. Energy intake gradually declined over the 4 weeks following the switch to the high-energy diet. In the second experiment, rats were fed high-fat diets that were either high or low in carbohydrate content and either high or low in energy content (kcal/g). Rats fed a high-fat diet that was high in energy and carbohydrate ate the most energy and gained the most body weight and carcass fat. In the third experiment, rats were fed high-carbohydrate diets varying in fat and cellulose content. Energy intake and body weight gain varied directly as a function of caloric density regardless of the fat or cellulose content of the diets. It is concluded that hyperphagia induced by feeding high-fat diets is not due to the high dietary fat content alone. Rather, high levels of fat, carbohydrate, and energy interact to produce overeating and obesity in rats fed high-fat diets.

Body fat distribution in females: metabolic consequences and implications for weight loss

The main function of adipose tissue is to store triglyceride during relative affluence and to break down this fat and release fatty acids and glycerol when needed. Both the deposition and degradation of lipid are under precise hormonal and neural control. Recently, it has become evident that adipose tissue is not homogeneous and that the regional distribution of fat may be important with respect to metabolism and hormonal responsiveness and, thus, of interest from a number of viewpoints. This review will focus on the physiological significance of differences in adipose tissue distribution and implications for the female. Included will be the hormonal and metabolic consequences of child bearing and the metabolic outcome for chronic disease risk. Furthermore, the influence of the distribution of adiposity on weight loss by diet and exercise, as well as changes in fat and lean tissue, will be examined. Possible directions for future research in this area will be discussed.

Somatotypes of weight lifters

The present paper reviews published studies on the body shape of weight lifters. The differences between the somatotype ratings of weight lifters studied using the Sheldon and the Heath-Carter methods, and the differences between performance levels and age groups of weight lifters are discussed. The differences in mean somatoplots among the weight lifters studied as a whole group, weight lifters divided into two, three or four groups according to body weight, and weight lifters considered according to the official weight classes, are assessed. Weight lifters in the lighter weight classes are found to be ectomorphic or balanced mesomorphs, while those in the heavier weight classes tend to be endomorphic mesomorphs. Ectomorphy decreases, whereas mesomorphy and endomorphy increase with weight class. When three age groups of weight lifters were compared within each weight class, the same pattern of differences between ages occurs. The younger lifters in each weight class have higher endomorphy and lower mesomorphy than the senior lifters. Ectomorphy is higher in the younger lifters below the weight class of 82.5 kg. Since significant differences in all three somatotype components between 10 weight classes of weight lifters and also within three age groups were noted, it will be necessary in future studies to consider the somatotypes of weight lifters according to the official weight classes.

Growth, body composition, hormonal and metabolic status in lambs treated long-term with growth hormone

The effect of long-term (10 weeks) treatment with growth hormone (GH) was investigated in twin lambs, one sibling being a control and the other treated with GH (0.1 mg/kg live weight per d). The lambs were fed on a concentrate-grass cube (9:1 w/w) diet at a daily rate of 40 g fresh weight/kg live weight. The average daily live-weight gain of the GH-treated lambs was 36% greater than that of the controls (307 v. 225 g/d, P less than 0.01). The carcass composition of the GH-treated lambs changed: fat content was decreased (P less than 0.01) and protein content was increased (P less than 0.05) when expressed relative to carcass dry matter. The absolute weights and the weights when expressed relative to fleece-free empty body of some muscles were significantly increased in GH-treated lambs. The mean retention times of both particulate- and liquid-phase components of the digesta were unchanged by GH treatment, when calculated for the rumen or for the entire gastrointestinal tract. The feed conversion ratio was significantly greater (P less than 0.01) in GH-treated lambs compared with controls. Nitrogen retained per g N intake was also significantly increased (P less than 0.05) by GH treatment. Plasma urea concentrations were decreased (P less than 0.05) and glucose concentrations were increased (P less than 0.01) in GH-treated lambs, whereas non-esterified fatty acid concentrations were unchanged. Plasma insulin and total insulin-like growth factor-1 concentrations progressively increased in GH-treated lambs as treatment time continued. They were significantly correlated after week 4 of treatment. Two types of hepatic GH-binding site were detected, with high and low affinities for GH. The capacities of both binding sites were significantly increased (P less than 0.05) in GH-treated lambs when expressed per unit microsomal protein but, when expressed per liver, only the capacity of the high-affinity site was increased.