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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of restricted diets on protein metabolism was studied in obese rats (obesity had been induced by ad libitum feeding of a diet containing 30% fat and 25% casein). The obese rats were fed on one of three restricted diets, each containing 5% fat, for 2 weeks (restricted feeding groups); a high-protein diet (HPD, 50% casein), a standard-protein diet (SPD, 25% casein), or a low-protein diet (LPD, 5% casein). The food intake was restricted to 5 g per day per rat. On the eleventh day, the rats were given [15N]glycine orally, and 4 days later, they were killed. The restricted feeding groups all showed similar weight losses (about 100 g), 2 weeks after the start of the restricted diet. The 15N distribution in whole body was measured and results were compared with those of control rats given 5%- or 30%-fat diet ad libitum. The whole-body distribution of 15N in the HPD group was similar to that in the rats fed ad libitum although the diet intake was restricted. The results suggested that the amount of protein in a restricted diet is important for maintenance of protein metabolism in obese rats.
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PMID:Effects of restricted diet on protein metabolism measured by [15N]glycine in high-fat-diet-induced obese rats. 343 39

Postprandial thermogenesis of 8 healthy males of normal body weight and 17 healthy obese subjects with a body weight gain of more than 10 kg per year was measured continuously by means of a respiratory chamber over 10 h after test meals of 1 and 2 MJ protein (casein) and 2 MJ carbohydrate (hydrolized starch). The total thermic response to all test meals was reduced by about 50% in the obese subjects. The thermic response was related to body weight, energy intake, resting metabolic rate and weight loss during restricted energy intake. The necessity for a careful characterization of the obese subjects in studies of thermogenesis and of efficiency of energy utilization in obesity is pointed out. It is suggested that thermic response to food can be considered as a suitable indicator for the distinction between people of different metabolic efficiency.
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PMID:Diet-induced thermogenesis in man: thermic effects of single protein and carbohydrate test meals in lean and obese subjects. 359 15

In this study, protein efficiency ratio and net protein utilization together with the kinetic estimates of protein turnover were used to compare the effect of different protein and fat sources in healthy rats. Male Sprague-Dawley CD rats were pair-fed different diets for 14 d. All diets were isonitrogenous and isocaloric, containing 10.4% protein, 10.9-11.4% fat, 31.9-32.8% carbohydrate and 43.5-44.5% moisture (wt/wt). After 14 d of feeding, protein efficiency ratio, net protein utilization, weight gain, intake, fat and protein content in the whole-body and fractional synthetic rates in various tissues were determined. Animals given diets containing medium-chain triglycerides (MCT) demonstrated decreased weight gain and fat content compared to the pair-fed controls receiving long-chain triglycerides (LCT). No difference was seen in protein content, net protein utilization and fractional synthetic rates in the liver and whole body of these MCT-fed rats when compared to those given LCT. Protein efficiency ratios in both of the MCT groups fed MCT + casein and MCT + soy protein were lower than those in the groups given LCT + casein. Although this study did not include a group for LCT and soy protein, these results suggest that MCT reduces the fat deposition without affecting the whole-body protein content. This may have implications for the treatment of obesity. Secondly, the protein efficiency ratio may not be a useful indicator of dietary protein quality when the fat source is MCT.
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PMID:Evaluation of the protein quality of diets containing medium- and long-chain triglyceride in healthy rats. 395 Jul 60

Thirty-two genetically lean and obese Yorkshire X Duroc crossbred castrated male pigs were divided within genetic line into two groups at 7 weeks of age. Eight pigs within each line were fed a diet low in fat and cholesterol (maize-soybean meal diet fortified with minerals and vitamins). The other group was fed a similar diet containing added beef tallow (11%) and dried egg yolk (1%). All pigs were fed ad libitum for 4 months when one-half of each group was slaughtered. All other pigs were continued on their respective diets at a restricted level of intake for an additional 5 months at which time the protein source of two pigs in each diet group within each genetic line was changed from soybean meal to casein. After an additional 6 months on their respective diets (16 months total duration of experiment) these pigs were slaughtered. Blood samples were taken monthly or bimonthly for total plasma cholesterol and triglycerides. At slaughter, the aorta was opened, stained with Sudan IV, and the stained area traced and measured planimetrically. Only a moderate rise occurred in plasma cholesterol and triglycerides of pigs fed high fat-high cholesterol diets. Genetically obese pigs were no more susceptible to diet-induced hypercholesterolemia and to the percentage of the surface area of the aorta stained with Sudan IV than were lean pigs. It is concluded that obesity per se is not necessarily associated with development of atherosclerosis in pigs and that innate ability to metabolize high dietary cholesterol is of greater importance than body fatness in determining the response to diet.
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PMID:Effect of obesity per se on plasma lipid and aortic responses to diet in swine. 399

Little is known about the behavioral, nutritional, and metabolic events that control dietary intake quality. Two experiments are described that manipulate nutritional conditions that have been hypothesized to affect dietary item choice so as to assess what effect, if any, the added factor of genetic obesity has in modifying the response to these manipulations. In the first experiment, 5 week old male obese and lean Zucker rats were fed a diet that varied in protein content (10%, 20%, or 60% casein by weight) for ten weeks. They were then allowed to select a diet from three separate macronutrient sources (casein, starch, or corn oil). Although body weights at the end of the 10 week maintenance period were markedly different, selection patterns were not influenced by pre-feeding different levels of protein. Obese rats selected a diet that was higher in fat and lower in protein than the diets composed by lean rats. In the second experiment, four groups of 7 month old obese and lean Zucker rats were given access to one of four diets that varied in protein content (5%, 10%, 15%, or 20% casein by weight). In addition, each rat was periodically given access to a 32% sucrose solution. Access to sucrose promoted increases in total caloric intake, independent of the protein content of the diet. Obese rats typically ate more calories per day than did their lean littermates. Results from these experiments suggest that food item selection is determined more by factors associated with obesity than by factors associated with dietary history.
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PMID:Nutritional influences on dietary selection patterns of obese and lean Zucker rats. 402

Synthesis of fatty acids was measured in the liver and in epididymal adipose tissue of sand rats and albino rats. In chow-fed sand rats the rate of hepatic lipogenesis, as measured by the incorporation of 3H2O into fatty acids, was four- to sevenfold higher than in albino rats and in sand rats on a low-calorie saltbush diet. The contribution of [14C]glucose to lipogenesis in sand rat liver was lower than in albino rats. In fed sand rats lipogenesis incorporating 3H2O was stimulated by casein but not by glucose. In adipose tissue, lipogenesis measured 1 h after administration of 3H2O was much lower in sand rats than in albino rats. In vitro incorporation of [14C]glucose or acetate into adipose tissue fatty acids was negligible. In adipose tissue, uptake of very-low-density lipoproteins (VLDL) and lipoprotein lipase activity were sevenfold higher than in albino rats. Activities of NADP-malate dehydrogenase, acetyl CoA carboxylase, and fatty acid synthetase were considerably higher in the liver of chow-fed sand rats than in albino rats. It was concluded that obesity in sand rats originates from hepatic lipogenesis without a significant contribution of local fatty acid synthesis in adipose tissue.
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PMID:Lipogenesis in the sand rat (Psammomys obesus). 634 15

Impaired protein deposition has been suggested to be a critical factor promoting the hyperphagia of the obese Zucker rat. The selection patterns of adult, male, genetically obese (fa/fa) and lean (Fa/-) Zucker rats were studied to determine if obese rats would select a diet that was higher in protein than the diet selected by lean littermates. Rats were provided ad libitum access to three macronutrient sources and were allowed to compose their own diets for 9 days. The three dietary items were: a vitamin + mineral--supplemented carbohydrate source (cornstarch), a vitamin + mineral--supplemented protein source (casein) and commercially available corn oil. Obese rats ate 43% more calories than lean littermates. Further, obese rats selected a diet that provided 12% of their total caloric intake as protein, 24% as carbohydrate and 64% as fat. Lean rats selected a diet that provided 33% of their total caloric intake as protein, 37% as carbohydrate and 30% as fat. These selection data are not consistent with the hypothesized importance of the role of dietary protein and its incorporation into lean body mass as a stimulus promoting the hyperphagia demonstrated by the genetically obese Zucker rats.
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PMID:Dietary self-selection and the Zucker rat. 706 14

Young female obese (ob/ob) and lean mice were fed a single diet containing 10 or 20% casein or were allowed to self-select from two diets containing 10 and 50, 20 and 60, or 30 and 70% casein for 3 weeks. Obese and lean mice offered a choice of two diets varying in protein-consumed 36% and 32%, respectively, of energy from protein. Although both obese and lean mice consumed more protein when allowed to self-select, each group maintained the same energy intake as observed when a single diet was fed. Because obese mice consumed more energy than lean mice, their self-selected intake of protein was 55% greater than observed in lean mice. The increased protein intake in self-selected obese mice was associated with a decreased tryptophan:large neutral amino acid ratio in their plasma. Average nitrogen retention was only slightly less in obese mice than in lean mice, but the sites of nitrogen deposition differed considerably. Obese mice retained only 35% of their nitrogen in the carcass (skeletal muscle and skeleton) while lean mice retained 58% of their nitrogen in the carcass. In summary, young obese mice allowed to self-select from two diets varying in protein and carbohydrate consumed more protein and more energy, but deposited less nitrogen in their carcasses, than lean mice. Hyperphagia in young obese mice is not directly linked to an increased demand for dietary protein.
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PMID:Protein intake regulation and nitrogen retention in young obese and lean mice. 719 28

The conversion of xanthine dehydrogenase to xanthine oxidase that produces oxygen radicals has been implicated in the ischemic injury to the myocardium and to the kidney. Xanthine dehydrogenase uses NAD as the electron acceptor to catalyze a reaction which does not produce any oxygen free radicals and may depress the conversion of xanthine dehydrogenase to xanthine oxidase. Nicotinamide is the preferred precursor for NAD. This study was conducted to examine the effect of an 18% casein diet supplemented with 0.5% nicotinamide on the activity of oxidoreductase and its two enzyme forms, xanthine dehydrogenase and xanthine oxidase, in kidney, heart and liver of female obese Zucker rats that spontaneously develop glomerulosclerosis, cardiomegaly and fatty liver. Lean litter mates were used as controls. Nicotinamide supplementation had no effect on the activities of these enzyme forms in the liver of either obese rats or lean rats. Obese rats fed the nicotinamide supplemented diet had higher activities of these enzyme forms in kidneys and hearts than unsupplemented diet fed obese rats, but this difference was not observed in lean rats. In unsupplemented rats, xanthine oxidase activity in the kidney was greater in lean rats than obese rats. Thus, the abnormalities observed in obese rats are unlikely attributable to the xanthine oxidase-mediated oxidant stress.
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PMID:Dietary nicotinamide supplementation increases xanthine oxidoreductase activity in the kidney and heart but not liver of obese Zucker rats. 761 99

The effects of dietary soybean protein on lipogenic enzyme gene expression in livers of genetically fatty rats (Wistar fatty) have been investigated. When Wistar fatty rats and their lean littermates (7-8-wk old) were fed a casein or soybean protein isolate diet containing hydrogenated fat (4% hydrogenated fat plus 1% corn oil) or corn oil (5%) for 3 wk, the hepatic messenger RNA concentrations and activities of lipogenic enzymes were significantly lower in rats fed soybean protein than in those fed casein, regardless of genotype or dietary fat. The conversion rates of thyroxine to triiodothyronine by liver microsomes and plasma triiodothyronine concentrations were lower in the fatty rats than in the lean rats and were significantly greater in rats fed soybean protein than in those fed casein. Conversely, plasma and liver triacylglycerol concentrations were lower in soybean protein-fed fatty and lean rats than in those fed casein. The body weight was less in the fatty rats fed soybean protein than in those fed casein after 3 wk of feeding. Moreover, dietary polyunsaturated fatty acids suppressed lipogenic enzyme gene expression in the lean rats but did not in the fatty rats. Dietary soybean protein appeared to be useful for the reduction of obesity.
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PMID:Soybean protein suppresses hepatic lipogenic enzyme gene expression in Wistar fatty rats. 863 9


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