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

The spiny mouse Acomys cahirinus, which exhibits beta-cell hyperplasia but low insulin secretion in captivity responded with hyperlipidemia without obesity or diabetes on a sucrose diet and became obese, and glucose-intolerant on a diet of fat-rich seeds. A three-month sucrose diet induced a marked rise in the activity of regulatory enzymes of glycolysis and lipogenesis in the liver but not in adipose tissue. There was also increased energy waste on this diet evident from a three-fold rise in the activity of hepatic mitochondrial FAD-glycerophosphate oxidase associated with an elevation in circulating triodothyronine. The obesity in mice maintained for three months on fat rich seeds was associated with moderate hyperglycemia, mild hyperinsulinemia and little change in circulating lipids. There was a decrease in the activity of glycolytic and lipogenic enzymes both in the liver and adipose tissue. Adipose tissue lipoprotein lipase activity rose, suggesting that the chylomicrons carrying the exogenous fat were better assimilated than the very-low-density lipoproteins synthesized from the dietary carbohydrate. Along with adipose tissue gain, triglyceride deposition was apparent in several muscles, accompanied by increased tissue free fatty acid, citrate and glycogen content. This suggested relation of increased muscle fat utilization with decreased glucose metabolism and insulin sensitiveness. Diverse responses to diets were thus elicited, which were particularly discernible in desert animals surviving on a limited caloric intake. Detailed follow up of these enzymatic and endocrine adaptation patterns to selective nutritional affluence may promote the understanding of the mechanisms leading to hyperlipidemia with leanness and normal glucose homeostasis versus obesity with diabetes but without hyperlipidemia.
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PMID:Intermediary metabolism during the development of obesity and diabetes in the desert rodent Acomys cahirinus. 711 67

The mitochondrial FAD-linked enzyme glycerophosphate dehydrogenase plays a key role in the pancreatic B-cell glucose sensing device. In the present study, the activity of this enzyme was examined in islets of fa/fa rats in which inherited diabetes mellitus is associated with obesity, hyperinsulinism and severe insulin resistance. The specific activity of both FAD-linked glycerophosphate dehydrogenase and glutamate dehydrogenase were decreased in islet and liver homogenates prepared from fa/fa, as compared to Fa/Fa, rats, this coinciding with a low ratio between glutamateoxalacetate and glutamate-pyruvate transaminase activity in both islet and liver extracts, islet hyperplasia, hyperinsulinemia and hepatic steatosis in the hyperglycemic fa/fa rats. It is speculated that a low activity of FAD-linked glycerophosphate dehydrogenase in the pancreatic B-cell may participate to the perturbation of glucose homeostasis in fa/fa rats, like in other animal models of non-insulin-dependent diabetes mellitus.
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PMID:Impaired FAD-glycerophosphate dehydrogenase activity in islet and liver homogenates of fa/fa rats. 783 41

Hyperinsulinemia accompanies obesity in human patients and experimental rodent models and exacerbates insulin resistance, but the causes of increased insulin secretion remain obscure. This review examines progress in defining biochemical and molecular beta-cell defects that have elucidated in the past 5 years. Some defects, such as decreased glucose transport, decreased mitochondrial FAD-linked glycerophosphate dehydrogenase activity, and altered anomeric specificity for glucose, become evident only after onset of non-insulin-dependent diabetes mellitus. Thus, these defects are unlikely to play a role in the pathogenesis of hyperinsulinemia in obesity. Other biochemical changes, including increased glucokinase and (or) hexokinase function, increased glucose cycling, and altered regulation of intracellular Ca2+ are present in obese nondiabetic animals and may therefore contribute to development of hyperinsulinemia. Few developmental studies have been performed to correlate onset of defects with environmentally and genetically mediated control mechanisms of beta-cell function. However, the availability of new molecular biology techniques should facilitate identification of factors causing hyperinsulinemia in obesity.
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PMID:beta-cell stimulus - secretion coupling defects in rodent models of obesity. 874 32

Diet plays an important role in the pathogenesis of colorectal cancer. Current prospective cohort studies and metaanalysis enable a reevaluation of how food or nutrients such as fiber and fat influence cancer risk. Based on the evidence criteria of the WHO/FAD, risk reduction by a high intake of fruit is assessed as possible, while a lowered risk by a high vegetable intake is probable. Especially raw vegetables and fruits seem to exert anticancer properties. The evidence of a risk reducing effect of whole grain relating to colorectal cancer is assessed as probable whereas the evidence of an increased risk by high consumption of refined white flour products and sweets is (still) insufficient despite some evidences. There is a probable risk reducing effect of milk and dairy products. e available data on eggs and red meat indicate a possible risk increasing influence. Stronger clues for a risk increasing effect have been shown for meat products leading to an evidence assessed as probable. Owing to varied interpretations of the data on fiber, the evidence of a risk reducing effect relating to colorectal cancer is assessed as possible or insufficient. The available data on alcohol consumption indicate a possible risk increasing effect. In contrast to former evaluations, diets rich in fat seem to increase colorectal cancer risk only indirectly as part of a hypercaloric diet by advancing the obesity risk. Thus, the evidence of obesity, especially visceral obesity, as a risk of colorectal cancer is judged as convincing today. Prospective cohort studies suggest that people who get higher than average amounts of folic acid from multivitamin supplements have lower risks of colorectal cancer. The evidence for a risk reducing effect of calcium, selenium, vitamin D and vitamin E on colorectal cancer is insufficient. As primary prevention, a diet rich in vegetables, fruits, whole grain products, and legumes added by low-fat dairy products, fish, and poultry can be recommended. In contrast the consumption of sweets, refined white flour products and meat products should be reduced.
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PMID:[Nutrition and colorectal cancer]. 1726 Jun 45

Adipocyte differentiation is controlled by many transcription factors, but few known downstream targets of these factors are necessary for adipogenesis. Here we report that retinol saturase (RetSat), which is an enzyme implicated in the generation of dihydroretinoid metabolites, is induced during adipogenesis and is directly regulated by the transcription factor peroxisome proliferator activated receptor gamma (PPARgamma). Ablation of RetSat dramatically inhibited adipogenesis but, surprisingly, this block was not overcome by the putative product of RetSat enzymatic activity. On the other hand, ectopic RetSat with an intact, but not a mutated, FAD/NAD dinucleotide-binding motif increased endogenous PPARgamma transcriptional activity and promoted adipogenesis. Indeed, RetSat was not required for adipogenesis when cells were provided with exogenous PPARgamma ligands. In adipose tissue, RetSat is expressed in adipocytes but is unexpectedly downregulated in obesity, most likely owing to infiltration of macrophages that we demonstrate to repress RetSat expression. Thiazolidinedione treatment reversed low RetSat expression in adipose tissue of obese mice. Thus, RetSat plays an important role in the biology of adipocytes, where it favors normal differentiation, yet is reduced in the obese state. RetSat is thus a novel target for therapeutic intervention in metabolic disease.
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PMID:Retinol saturase promotes adipogenesis and is downregulated in obesity. 1913 8