Thyroid Function and Energy Intake During Weight Gain Following Treatment of Hyperthyroidism

Objective: Individuals with hyperthyroidism lose weight despite increased appetite and food intake, and weight is regained after treatment of hyperthyroidism. We asked whether this weight regain is purely a function of lowered metabolic rate coincident with lowered thyroid hormone concentrations or if the weight gain is related to food-energy overconsumption.

Methods: Ten unselected patients with hyperthyroidism treated with ¹³¹I were studied. The following measurements were made at 0, 1, 2, 3, 6, and 12 months: total food energy, carbohydrate, fat and protein consumption; serum thyroxine (T₄); serum triiodothyronine (T₃); T₃ resin uptake; serum thyroid stimulating hormone (TSH); weight; height; and 24-hour urinary urea excretion.

Results: Inverse changes in body weight and food energy consumption/kg throughout the period of observation was a striking finding (mean initial weight 67.1 ± 5 kg, final weight 76.4 kg ± 3 kg, premorbid weight 77.1 ± 5 kg). The initial and final food energy intake was 3005 ± 199 and 2597 ± 137 Kcal/24 hrs, respectively. The thyroid hormone concentrations declined inversely relative to weight gain during the first months of the study, but later the thyroid hormones increased while weight gain continued. Initial serum T₄ 15.0 ± 1 value at three months was 4.0 ± 1.0 mg/dl, final T₄ 11.0 ± 1.

Conclusion: We conclude that weight gain following treatment of hyperthyroidism is due to 1) reduction in metabolic rate consequent upon the decreased thyroid hormone concentrations and 2) food energy intake which was initially greater than required to maintain individuals’ premorbid weight. As body weight increased, food intake declined and both reached an asymptotic limit.     

Leptin and body weight regulation in patients with anorexia nervosa before and during weight recovery

BACKGROUND: Leptin has been considered a starvation hormone, but its role in malnourished patients is unknown. OBJECTIVE: We aimed to characterize the role of leptin in metabolic adaptation in women with anorexia nervosa (AN). DESIGN: In a cross-sectional study, 57 women with AN [mean (+/-SD) body mass index (kg/m(2)) on admission: 15.2 +/- 1.5] were compared with 49 healthy, normal-weight women (mean body mass index: 22.3 +/- 2.3). Nineteen patients were reinvestigated during weight gain 43 and 84 d after baseline. We measured serum concentrations of leptin, soluble leptin receptor, insulin, ghrelin, and thyroid hormones [thyrotropin, triiodothyronine (T(3)), and thyroxine]; fat mass (FM) and fat-free mass (FFM); resting energy expenditure (REE); energy intake; and eating behavior. RESULTS: Compared with values in the control women, leptin, T(3), REE, FM, and FFM were lower in the women with AN, but the leptin secretion rate was not significantly different. Leptin correlated with FM (r = 0.83, P < 0.001), T(3) (r = 0.68, P < 0.001), respiratory quotient (r = -0.47, P < 0.001), and REE (r = 0.58, P < 0.001). The association with REE weakened after adjustment for FFM and disappeared after further adjustment for T(3). Hunger and appetite had positive, whereas satiety and restraint had negative, associations with leptin. During weight gain (9.0 +/- 3.3 kg in 84 d), serum leptin and the leptin secretion rate increased. Changes in leptin secretion were associated with energy intake and REE. The initial changes in the leptin secretion rate (ie, the difference between baseline and 43 d) were negatively associated with changes in body weight from 43 to 84 d. CONCLUSIONS: Leptin contributes to metabolic adaptation in women with AN. The leptin response is associated with weight gain.     

Alterations in endothelium-associated proteins and serum thyroid hormone concentrations in anorexia nervosa.

Plasma concentrations of endothelium-associated proteins (EAP) (plasma fibronectin (PFN), angiotensin-converting enzyme, factor VIII-related antigen (F VIII-R:Ag)) and tissue plasminogen activator and serum thyroid hormone concentrations were studied in nine patients with anorexia nervosa (AN), before and after weight gain. Before weight gain (-35.9 (SE 2.3)% of standard body-weight) PFN was significantly reduced and F VIII-R:Ag was significantly increased in AN patients compared with the concentrations in control subjects (211.5 (SE 14.9) v. 274.7 (SE 16.6) micrograms/ml, P < 0.05; 129.2 (SE 14.1) v. 88.2 (SE 9.7) %, P < 0.05 respectively). Serum triiodothyronine (T3) and free T3 levels were also significantly lower before weight gain in AN patients (0.85 (SE 0.07) v. 1.53 (SE 0.08) nmol/l, P < 0.001; 2.57 (SE 0.23) v. 5.31 (SE 0.34) pmol/l, P < 0.001 respectively), although serum thyroxine (T4), free T4, and thyrotropin concentrations were within the normal range throughout the study periods. Following weight gain, PFN and F VIII-R:Ag concentrations normalized as did the thyroid hormone levels. The incremental changes in PFN levels correlated significantly with those in serum thyroid hormone concentrations (T3, r 0.79, P < 0.01; free T3, r 0.84, P < 0.01). These findings suggest that PFN levels may be directly related to serum T3 concentrations in AN patients.     

Exogenous recombinant human growth hormone effects during suboptimal energy and zinc intake

BACKGROUND: Energy and Zinc (Zn) deficiencies have been associated with nutritional related growth retardation as well as growth hormone (GH) resistance. In this study, the relationship between suboptimal energy and/or Zn intake and growth in rats and their response to immunoreactive exogenous recombinant human GH (GHi), was determined. RESULTS: Rats treated with GHi and fed ad-libitum energy and Zn (100/100) had increased IGFBP-3 (p < 0.05) as compared with NSS (215 +/- 23 vs. 185 +/- 17 ng/ml) along with similar body weight gain. Rats treated with GHi and fed suboptimal energy and full Zn (70/100) had significantly increased weight gain (109.0 +/- 18.2 vs. 73.8 +/- 11.0 g) and serum IGF-I levels (568 +/- 90 vs. 420 +/- 85 ng/ml), along with decreased total body water (TBW; 61.0 +/- 1.6 vs. 65.7 +/- 2.1%) as compared to NSS controls. However, body weight gain was reduced (p < 0.05) as compared with rats fed ad-libitum energy. Growth hormone treated rats fed only suboptimal Zn (100/70), had increased weight gain (217.5 +/- 13.2 vs. 191.6 +/- 17.9 g; p < 0.05) compared to those given NSS. These rats gained weight in similar amounts to those fed full Zn. Rats treated with GHi and fed both suboptimal energy and Zn (70/70) showed similar results to those fed suboptimal energy with appropriate Zn (70/100), along with significant increases in IGFBP-3 levels (322 +/- 28 vs. 93 +/- 28 ng/ml). All restricted rats had reduced 24-h EE (kcal/100 g BW) and physical activity index (oscillations/min/kg BW) and GHi did not overcome these effects. CONCLUSION: These results suggest that GHi enhances weight gain in rats with suboptimal energy and Zn intake but does not modify energy expenditure or physical activity index. Suboptimal Zn intake did not exacerbate the reduced growth or decrease in energy expenditure observed with energy restriction.     

Observations in energy and macronutrient intake during prolonged bed-rest in a head-down tilt position

OBJECTIVE: to report observations in energy and macronutrient intakes, and body weight during prolonged bed-rest in a head down tilt (HDT) position. DESIGN: open study, each subject was his own control, and was studied during 14 days of baseline, 42 days of -6 degrees HDT bed-rest, and 12 days of recovery. SUBJECTS: eight healthy young man were recruited, one dropped out. METHODS: energy and macronutrient content of the diet were calculated from weighed amounts of food consumed and French food composition tables. RESULTS: body weight declined during HDT (74.0+/-3.2 to 71.8+/-3.2 kg, P< 0.001) and increased during recovery (72.7+/-3.2 kg, P< 0. 001). Energy intake decreased during HDT (by 17% after 4-5 weeks) and increased during recovery but remained lower than during baseline (P< 0.001). During HDT fat intake, expressed by a percentage of energy, decreased (P< 0.01) while carbohydrate increased (P= 0.04); protein intake did not change (P= 0.08). The reverse trends were observed during recovery. CONCLUSIONS: the present study reports a spontaneous reduction in energy and relative fat intake during prolonged HDT bed rest. We believe that these findings have implications for the clinical setting.     

Is growth hormone a feasible adjuvant in the treatment of children after small bowel resection?

The aim of our study was to assess the metabolic consequences of short-term administration of growth hormone in children after gut resection and influence on polyamine production in red blood cells (RBC). Twelve children aged 4-60 months were studied. All children remained on parenteral nutrition and 11 also received oral feeding. Total non-protein energy intake was 429 +/- 86 kJ/kg body weight (BW)/day. Recombinant growth hormone (GH) was administered subcutaneously at a dose of 0.3 IU/kg BW/day for 10 days. Resting energy expenditure (REE; kJ/kg BW/day) was: 316.07 +/- 54.08 before and 346.04 +/- 54.40 during GH administration (P < 0.02), but daily weight gain before GH administration was significantly lower than during treatment. A significant increase of polyamine concentrations was observed in the RBC (spermidine: 30.1 +/- 15.1 and 43.8 +/- 24.9 nmol/ml packed RBC, P < 0.003; spermine: 15.6 +/- 5.1 and 19.6 +/- 10.6 nmol/ml packed RBC, P < 0.02) and in jejunal mucosa (spermidine: 172.10 +/- 142.35 nmol/g tissue and 193.92 +/- 108.15 nmol/g tissue). The authors concluded that increased polyamine concentrations in the RBC and jejunal mucosa reflect a cellular response to GH administration. The anabolic effect of GH results in higher weight gain, although increased REE may indicate increased energy requirements during GH treatment.     

Effects of changes in body weight on carbohydrate metabolism, catecholamine excretion, and thyroid function

BACKGROUND: Weight gain and loss increases and decreases energy expenditure, respectively, out of proportion to changes in metabolic mass. OBJECTIVE: We hypothesized that changes in energy expenditure associated with weight gain or loss were due in part to changes in catecholamine release, thyroid hormones, carbohydrate utilization, or a combination thereof. METHODS: Urinary catecholamine excretion, serum thyroid hormone concentrations, and results of 3-h oral-glucose-tolerance tests were examined in obese and never-obese subjects at their usual weights, during weight loss or gain, and at stable weights 10-20% below or 10% above usual. RESULTS: Urinary norepinephrine excretion decreased significantly during and after weight loss and increased during and after weight gain. Serum concentrations of reverse triiodothyronine increased significantly during and after weight loss, whereas serum concentrations of triiodothyronine increased significantly (by approximately 0%) during and after weight gain. Serum insulin and glucose concentrations during the oral-glucose-tolerance test increased significantly after weight gain in obese subjects. The percentage change in urinary norepinephrine excretion and in serum concentrations of triiodothyronine were significantly correlated with percentage changes in energy expenditure and with each other. CONCLUSIONS: Changes in body weight were associated with changes in catecholamine excretion and thyroid hormones, which might-by virtue of the effects on energy expenditure-have favored a return to usual body weight. Weight gain induced more apparent insulin resistance in the obese than the never-obese subjects, suggesting a threshold effect of total body fat on this phenomenon.     

Effect of food restriction on tissue carnitine concentration in rats

The effect of feeding different amounts of a standard laboratory pellet diet on tissue carnitine concentration was studied in four groups of rats. Group I was fed ad libitum, whereas food intake was restricted to 25, 20, and 15g protein/kg body weight/day in group II, III, and IV, respectively. The intake of food, protein, energy and carnitine was constant and adjusted to actual body weight in groups 2-4. Six weeks food restriction had no effect on muscle carnitine. Restricted diet caused lowered concentrations of carnitine in serum (group I, fed ad libitum, total 95.0 +/- 13.8, free 80.2 +/- 2.7; group II total 78.4 +/- 8.4, free 56.9 +/- 4.7; group III total 81.7 +/- 8.8, free 66.0 +/- 8.8; and group IV total 73.8 +/- 8.7, free 59.5 +/- 7.6 mumol/l) and urinary carnitine excretion (group I, total 7.1 +/- 3.3, free 6.3 +/- 3.1; group II, total 2.5 +/- 0.7, free 2.2 +/- 0.7; group III, total 1.9 +/- 0.8, free 1.6 +/- 0.8; and group IV, total 1.3 +/- 0.4 free 1.1 +/- 0.3 mumol/day). In contrast, the liver carnitine tended to increase when dietary intake was reduced (group I total 1.1 +/- 0.1, free 1.0 +/- 0.1; group II total 1.5 +/- 0.2, free 1.4 +/- 0.2; group III total 1.3 +/- 0.1, free 1.1 +/- 0.1; and group IV total 1.5 +/- 0.2, free 1.4 +/- 0.2 mumol/g dry wt). The highest liver carnitine concentrations were observed during the lowest dietary intake when also the serum and urine carnitine were lowest. We conclude that the amount of food intake has a direct impact on carnitine concentrations in the liver, serum, and urine while muscle carnitine concentration remains relatively stable despite wide variations in food intake.     

Staggered meal consumption facilitates appetite control without affecting postprandial energy intake

Meal pattern may influence hormone and appetite dynamics and food intake. The objective of the study was to determine the effects of staggered compared with nonstaggered meal consumption on hormone and appetite dynamics, food reward (i.e. "liking," "wanting"), and subsequent energy intake. The study was conducted in a randomized cross-over design. Participants (n = 38, age = 24 ± 6 y, BMI = 25.0 ± 3.1 kg/m(2)) came to the university twice for consumption of a 4-course lunch (40% of the daily energy requirements) in 0.5 h (nonstaggered) or in 2 h with 3 within-meal pauses (staggered) followed by ad libitum food intake. Throughout the test sessions, glucagon-like peptide (GLP)-1, peptide tyrosine-tyrosine (PYY(3-36)), ghrelin, appetite, and food reward were measured. In the staggered compared with nonstaggered meal condition, peak values of GLP-1, PYY(3-36), and satiety were lower and time to peak values were higher (P < 0.02); the nadir value of hunger was higher, and time to nadir values of ghrelin and hunger were higher (P < 0.0001). Prior to ad libitum food intake, GLP-1 concentrations and satiety ratings were greater, ghrelin concentrations and hunger ratings were smaller, and food "wanting" was less in the staggered compared with nonstaggered meal condition (P < 0.05). However, this did not affect ad libitum energy intake (1.7 ± 0.3 vs. 1.9 ± 0.2 MJ). In conclusion, staggered compared with nonstaggered meal consumption induces less pronounced hormone and appetite dynamics. Moreover, it results in higher final GLP-1 concentrations and satiety ratings, lower ghrelin concentrations and hunger ratings, and lower food "wanting" prior to ad libitum food intake. However, this was not translated into lower energy intake.     

Dietary patterns in patients with advanced cancer: implications for anorexia-cachexia therapy

BACKGROUND: Severe malnutrition and wasting are considered hallmarks of advanced malignant disease, and clinical research into anorexia-cachexia therapy and nutritional support for cancer patients is ongoing. However, information on typical dietary intakes and food choices for this population is notably lacking; proposed therapies for anorexia and wasting are not framed within the context of current intake. OBJECTIVE: The objective of the study was to characterize the food intake patterns of patients with advanced cancer. DESIGN: Patients with advanced cancer (n = 151) recruited from a regional cancer center and palliative-care program completed a 3-d dietary record a mean (+/-SD) 8 +/- 7 mo before death. Food items were categorized according to macronutrient content and dietary use and subsequently entered into cluster analysis. RESULTS: Wide variations in intakes of energy (range: 4-53 kcal . kg body wt(-1) . d(-1); x +/- SD: 25.1 +/- 10.0 kcal . kg body wt(-1) . d(-1)) and protein (range: 0.2-2.7 g . kg body wt(-1) . d(-1); x +/- SD: 1.0 +/- 0.4 g . kg body wt(-1) . d(-1)) were observed. Even the subjects with the highest intakes had a recent history of weight loss, which suggests that the diets of those persons were consistently inadequate for weight maintenance. Cluster analysis found 3 dietary patterns that differed in food choice and caloric intake. Low intakes and a high risk of weight loss were associated with decreased frequency of eating and dietary profiles with little variety and unusually high proportions of liquids. CONCLUSION: These data provide a glimpse into dietary habits toward the end of life. Unique dietary patterns were found in this nutritionally vulnerable patient population.     

Food groups as predictors for short-term weight changes in men and women of the EPIC-Potsdam cohort

This study examined the effect of food group intake on subsequent 2-y weight change. Food-frequency questionnaire-based food intake data of 17,369 nonsmoking subjects of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort were examined in their relation to a subsequent weight change. Dietary data, collected from 1994 to 1998, were grouped into 24 food groups. Weight change per year follow-up was the outcome of interest; large weight gain was defined as > or =2 kg; small weight gain as > or =1 kg to <2 kg; large weight loss as < or = -2 kg; small weight loss as < or = -1 kg to > -2 kg and weight maintenance as +/- 1 kg. For each food group, a separate polytomous logistic regression model with stable weight as the reference group was constructed, controlling for age, body mass index, previous weight change, and behavioral and lifestyle factors. Odds ratios (OR) and 95% confidence intervals (CI) estimated the increase in risk associated with each 100 g/d increment in food group intake. In women, consumption of high energy, high fat food groups significantly predicted large weight gain, e.g., fats (OR = 1.75; 95% CI, 1.01-3.06), sauces (OR = 2.12; 95% CI, 1.17-3.82) and meat (OR = 1.36; 95% CI, 1.04-1.79), and the consumption of cereals predicted large weight loss (OR = 1.43; 95% CI, 1.09-1.88). In men, intake of high energy, high sugar foods, i.e., sweets, was significantly predictive of large weight gain (OR = 1.48; 95% CI, 1.03-2.13). Our data show that a diet rich in high fat and high energy foods predicts short-term weight gain even if controlled for many potential confounding factors.     

Control of physiological response in the rat by dietary nutrient concentration

In three separate experiments, growing, male Sprague-Dawley rats were fed diets which contained: 1) graded levels of fiber 0-70%, 2) graded levels of pyridoxine 1-10 mg/kg diet, and 3) graded levels of casein 0-30%. The following physiological responses were measured in each respective experiment: 1) food intake, weight gain, serum triglycerides, 2) food intake, weight gain, SGPT levels, and 3) weight specific food intake, weight gain, relative testes weight. Diets were fed as a single source, and in each case, physiological response could be predicted as a function of dietary nutrient concentration. When self-selection is prevented, rats establish new steady-state response profiles, which are sigmoidal in shape and dependent on the interaction of the rats' genetic potential with the environmental configuration.     

Evaluation of transthyretin as a monitor of protein-energy intake in preterm and sick neonatal infants

In the past, weight and weight gain have been the two parameters used frequently in neonatal units to monitor nutrition among high-risk infants. Our investigation sought to assess how several anthropometric measures (weight, length, head circumference, arm:head circumference ratio, and tricep skinfold) and serum albumin, transthyretin, and transferrin concentrations reflect protein and energy intake. After monitoring 42 preterm and 40 sick infants over 3 consecutive weeks, we found that transthyretin concentration proved the only serum protein which accurately measured energy and protein intakes in less than 1 week from dietary manipulation. Among preterm infants, as protein and energy intakes rose, transthyretin concentration increased significantly (p less than 0.001). Preterm infants ingested 79 +/- 39 kcal/kg/day and 2.04 +/- 1.02 g protein/kg/day at the first assessment point after birth and rose to 103 +/- 34 kcal/kg/day and 2.64 +/- 0.94 g protein/kg/day. Likewise, transthyretin measured 10.83 +/- 3.91 mg/dl at the initial measurement and rose to 14.80 +/- 4.44 at the second measurement time. Although protein intakes measured slightly lower in the sick group, their intakes correlated to transthyretin concentration (assessment time 1, r = 0.39; time 2, r = 0.33; time 3, r = 0.33). Thus, transthyretin concentration in neonatal infants offers a rapid, accurate, and moderately inexpensive way to monitor protein-energy adequacy.     

Plasma concentrations of free triiodothyronine predict weight change in euthyroid persons

BACKGROUND: Factors that influence energy metabolism and substrate oxidation, such as thyroid hormones (THs), may be important regulators of body weight. OBJECTIVE: We investigated associations of THs cross-sectionally with obesity, energy expenditure, and substrate oxidation and prospectively with weight change. DESIGN: Euthyroid, nondiabetic, healthy, adult Pima Indians (n = 89; 47 M, 42 F) were studied. Percentage body fat (%BF) was measured by using dual-energy X-ray absorptiometry; sleeping metabolic rate (SMR), respiratory quotient, and substrate oxidation rates were measured in a respiratory chamber. Thyroid-stimulating hormone (TSH), free thyroxine (T(4)), free triiodothyronine (T(3)), and leptin concentrations were measured in fasting plasma samples. RESULTS: TSH, but neither free T(3) nor free T(4), was associated with %BF and leptin concentrations (r = 0.27 and 0.29, respectively; both: P 相似文献   

Decreased resting metabolic rate in ballet dancers with menstrual irregularity.

We studied 21 ballet dancers aged 19.4 +/- 1.4 years, hypothesizing that undernutrition was a major factor in menstrual irregularity in this population. Menstrual history was determined by questionnaire. Eight dancers had always been regular (R). Thirteen subjects had a history of menstrual irregularity (HI). Of these, 2 were currently regularly menstruating, 3 had short cycles, 6 were oligomenorrheic, and 2 were amenorrheic. Subjects completed a weighed dietary record and an Eating Attitudes Test (EAT). The following physiological parameters were measured: body composition by anthropometry, resting metabolic rate (RMR) by open-circuit indirect calorimetry, and serum thyroid hormone concentrations by radioimmunoassay. R subjects had significantly higher RMR than HI subjects. Also, HI subjects had lower RMR than predicted by fat-free mass, compared to the R subjects. Neither reported energy intake nor serum thyroid hormone concentrations were different between R and HI subjects. EAT scores varied and were not different between groups. We concluded that in ballet dancers, low RMR is more strongly associated with menstrual irregularity than is current reported energy intake or serum thyroid hormone concentrations.     

S 23521 decreases food intake and body weight gain in diet-induced obese rats

OBJECTIVE: To investigate the effect of S 23521, a new glucagon-like peptide-1-(7-36) amide analogue, on food intake and body weight gain in obese rats, as well as on gene expression of several proteins involved in energy homeostasis. RESEARCH METHODS AND PROCEDURES: Lean and diet-induced obese rats were treated with either S 23521 or vehicle. S 23521 was given either intraperitoneally (10 or 100 microg/kg) or subcutaneously (100 microg/kg) for 14 and 20 days, respectively. Because the low-dose treatment did not affect food intake and body weight, the subcutaneous treatment at high dose was selected to test the effect on selected end-points. RESULTS: Treated obese rats significantly decreased their cumulative energy intake in relation to vehicle-treated counterparts (3401 +/- 65 vs. 3898 +/- 72 kcal/kg per 20 days; p < 0.05). Moreover, their body weight gain was reduced by 110%, adiposity was reduced by 20%, and plasma triglyceride levels were reduced by 38%. The treatment also improved glucose tolerance and insulin sensitivity of obese rats. Regarding gene expression, no changes in uncoupling protein-1, uncoupling protein-3, leptin, resistin, and peroxisome proliferator-activated receptor (PPAR)-gamma were observed. DISCUSSION: S 23521 is an effective glucagon-like peptide-1-(7-36) amide analogue, which induced a decrease in energy intake, body weight, and adiposity in a rat model of diet-induced obesity. In addition, the treatment also improved glucose tolerance and insulin sensitivity of obese rats. These results strongly support S 23521 as a putative molecule for the treatment of obesity.     

Energy metabolism and body composition of young pigs given low-protein diets

The energy metabolism of young pigs offered low-protein diets to appetite or a normal starter (diet 1, 225 g crude protein (nitrogen X 6.25; CP)/kg dry matter (DM] to maintain zero energy balance was studied using indirect calorimetry and slaughter. The treatments were: T1, diet 1; T2, 46 g CP/kg DM; T3, 21 g CP/kg DM; T4, 17 g CP/kg DM; T5, 21 g CP/kg DM and no supplemental thiamin. Daily heat production (kJ/d per kg body-weight (W)0.75) declined on all treatments from a pre-experimental value of 613. The greatest decline was observed in T1 pigs where the final value was 375. There was a progressive reduction in energy intake from 5.4 MJ/d for T2 pigs to 3.0 MJ/d for T4 and T5 pigs (P less than 0.001). The mean intake of T1 pigs was 2.3 MJ/d. There were highly significant treatment differences (P less than 0.001) in gain of live-weight and in the gain of carcass DM, CP, fat and energy. There were marked treatment effects on body composition. T1 pigs showed a decrease in the proportion of carcass fat and an increase in the proportion of carcass CP during the experiment while the other four treatments caused large increases (P less than 0.001) in carcass DM and fat content and no change in CP content. These changes resulted in large differences in the energy content of the gain, the mean values (MJ/kg) being 0.6, 35.5 and 88 for T1, T2 and T3 pigs respectively. T4 and T5 caused energy gain coupled with weight loss. A linear regression of energy retention (ER; MJ/d per kg W0.75) on metabolizable energy (ME) intake yielded the equation ER = 0.78 ME--0.365, r0.96. These results indicate that heat production declines when the growth rate of young pigs is reduced either by restriction of energy or of protein intake. They do not support the suggestion that low-protein diets give rise to increased 'diet-induced' thermogenesis.     

In vitro lipid metabolism, growth and metabolic hormone concentrations in hyperthyroid chickens.

Indian River male broiler chickens growing from 7 to 28 d of age were fed on diets containing energy:protein values varying from 43 to 106 MJ/kg protein and containing 0 or 1 mg triiodothyronine (T3)/kg diet to study effects on growth, metabolic hormone concentrations and in vitro lipogenesis. In vitro lipid synthesis was determined in liver explants in the presence and absence of ouabain (Na+, K(+)-transporting ATPase (EC 3.6.1.37) inhibitor) to estimate the role of enzyme activity in explants synthesizing lipid. Growth and feed consumption increased (P < 0.01) when the energy:protein value decreased from 106 to 71 MJ/kg protein; however, both variables decreased as the value was further decreased from 53 to 43 MJ/kg protein. Triiodothyronine depressed (P < 0.01) growth, but not food intake. Large energy:protein diets (> 53 MJ/kg protein) and dietary T3 lowered (P < 0.01) plasma growth hormone. Large energy:protein diets (> 53 MJ/kg protein) increased (P < 0.01) lipogenesis, plasma growth hormone (GH) and decreased plasma insulin-like growth factor 1 (IGF-1). Also, T3 decreased plasma GH, IGF-1 in vitro lipogenesis. Ouabain inhibited a greater proportion of in vitro lipogenesis in those explants synthesizing fat at a high rate. Both dietary T3 and in vitro ouabain decrease lipogenesis, but, when combined, the effects are not cumulative.     

Factors associated with the increase in resting energy expenditure during refeeding in malnourished anorexia nervosa patients

BACKGROUND: In malnourished anorexia nervosa (AN) patients, body-weight gain during refeeding is slowed by an increase in resting energy expenditure (REE). OBJECTIVE: The objective of the study was to identify factors associated with the increase in REE during refeeding. DESIGN: Before and 8, 30, and 45 d after the beginning of refeeding, REE was studied by indirect calorimetry in 87 female AN patients [x +/- SD age: 23.4 +/- 7.9 y; body mass index (in kg/m2) 13.2 +/- 1.3]. Energy intake, body composition (by bioelectrical impedance analysis), physical activity, smoking behavior, abdominal pain, anxiety, depressive mood, serum thyrotropin and thyroid hormone, and urinary catecholamines were measured. REE was also evaluated in 18 patients after 1 y of recovery. RESULTS: By day 8, REE increased from 3.84 +/- 0.6 to 4.36 +/- 0.59 MJ/d (P < 0.01). This increase (13.4%) was significantly (P <0.01) greater than that expected on the basis of the increase in fat-free mass (FFM; 1.6%). Thereafter, the ratio of REE to FFM remained high and, in multivariate analysis, was significantly related to 4 factors: energy intake (P <0.01), anxiety (P <0.01), abdominal pain (P <0.05), and depressive mood (P <0.05). The ratio also increased significantly with physical activity (P <0.01) and cigarette smoking (P <0.02). This rise in REE leveled off after recovery from AN. CONCLUSION: In AN patients, the rise in REE observed during refeeding was independently linked to anxiety level, abdominal pain, physical activity, and cigarette smoking, and it contributed to resistance to weight gain.