Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020505 (hyperphagia)
 6,116 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Contrary to normal rats, diabetic rats are known to develop marked hypercholesterolemia when fed a cholesterol-enriched diet. The triggering factor involved in this hyperresponse has not been identified. With the aim of clarifying the role of the intestinal acyl-CoA:cholesterol acyltransferase (ACAT), we studied the effects of a high fat diet and the changes of intestinal ACAT activity during the early development of streptozotocin-diabetes in rats. Feeding diabetic rats with a diet enriched in cholesterol and saturated fat produced an increase in plasma and in tissue cholesterol as early as 3 days after streptozotocin injection in the absence of hyperphagia. Under these experimental conditions, treatment with insulin or with the ACAT inhibitor CL-277082 significantly reduced the plasma cholesterol to levels measured in nondiabetic rats fed the same high fat diet. An increase in [14C]cholesterol in plasma very low density lipoprotein was observed after oral administration of labeled cholesterol to 3-day diabetic rats. In parallel experiments, the direct measurement of small intestine microsomal ACAT activity revealed an increase, averaging 288% in diabetic rats 3 days after diabetes induction. This change in ACAT activity occurred simultaneously with an increase in plasma glucagon and was normalized by insulin treatment. The induction of intestinal ACAT activity in diabetic rats, its modulation by insulin, and the hypocholesterolemic effects of insulin or CL-277082 treatment clearly indicate that ACAT activity plays a major role in the initiation of diabetes-associated hypercholesterolemia.
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PMID:Role of the intestinal acyl-CoA:cholesterol acyltransferase activity in the hyperresponse of diabetic rats to dietary cholesterol. 143 72

The effect of diabetes control on the activities of hydroxymethylglutaryl-CoA reductase (HMG-CoA reductase), cholesterol acyltransferase (ACAT), and phenol 2-monooxygenase, the major enzymes regulating cholesterol metabolism, was determined in alloxan-induced diabetic rabbits, and the results obtained were correlated with lipid and lipoprotein levels. Although intestinal HMG-CoA reductase activity was significantly increased (P less than 0.001) in poorly controlled compared with moderately controlled diabetic rabbits, there was a significant reduction in the activities of intestinal ACAT (P less than 0.01), hepatic HMG-CoA reductase (P less than 0.05) and ACAT (P less than 0.001), and phenol 2-monooxygenase (P less than 0.01). The poorly controlled animals were hypercholesterolemic (P less than 0.01), and this was reflected in the very-low-density and high-density lipoprotein fractions. Serum cholesterol levels in the nondiabetic and moderately controlled diabetic groups were similar. This increase in intestinal HMG-CoA reductase activity in the poorly controlled diabetic animals occurred in the absence of hyperphagia. Although abnormalities in cellular cholesterol metabolism could be partly responsible for the alterations in serum cholesterol levels in diabetes, the precise mechanisms underlying these enzymatic changes have yet to be elucidated.
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PMID:Cholesterol metabolism in alloxan-induced diabetic rabbits. 233 20

Postprandial hyperlipidemia (PH) is recognized as a significant risk factor for cardiovascular disease. The present study, involving rats with streptozotocin (STZ)-induced diabetes, was performed to establish a PH model and to examine the relation between small intestinal acyl-coenzyme A:cholesterol acyltransferase (ACAT) activity and serum lipid levels in the postprandial state. The small intestinal ACAT activities in normal rats during the experimental period were 4 to 5 pmol/mg protein per minute. In contrast, in the diabetic rats, the ACAT activities were 2 to 3 times higher than activities seen in normal rats from 7 to 21 days after the STZ injection in the absence of a high fat diet and hyperplasia in the gut. In an oral fat-loading test that used diabetic rats that had been injected with STZ (60 mg/kg) intravenously 14 days previously, the postloading changes in the serum concentrations of total cholesterol (TC) and triglyceride (TG) were significantly greater in the diabetic rats than in normal rats. Single oral administration of (1s,2s)-2-[3-(2,2-dimethylpropyl)-3-nonylureido]cyclohexane- 1-yl 3-[(4R)-N-(2,2,5,5-tetramethyl-1, 3-dioxane-4-carbonyl)amino]propionate (F-1394, 3 to 30 mg/kg), a potent ACAT inhibitor, suppressed the post-fat-loading elevation of serum TC levels in the diabetic rats in a dose-dependent manner without affecting serum glucose levels. Furthermore, the small intestinal ACAT activity, serum TG levels, and lymphatic absorption of TC and TG in the rats that were administered F-1394 (30 mg/kg) were reduced by approximately 90%, 70%, 30%, and 15%, respectively. This is the first evidence that elevated ACAT activity in the gut, unlike hyperplasia and hyperphagia, induces PH in rats. Our results strongly suggest that F-1394 may be a potential treatment for PH in humans.
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PMID:Postprandial hyperlipidemia in streptozotocin-induced diabetic rats is due to abnormal increase in intestinal acyl coenzyme A:cholesterol acyltransferase activity. 1063 14