title: Effect of type of diet and feeding status on modulation of hepatic HMG-CoA reductase in rats.
abstract: The effect of diet type and feeding status on hepatic HMG-CoA reductase (HMGR) [mevalonate: NADP+ oxidoreductase (acylating CoA); EC 1.1.1.34] was studied in rats. Animals fed a ground, commercial, stock diet exhibited higher expressed and total activities of HMGR in the fed state than animals fed a semi-purified diet. The differences did not appear in meal-trained animals when measured before the onset of the meal after a 22-hr fast. When expressed activity was taken as a per cent of total activity, fed animals from both diet groups used about 10% of their available activity. When animals on commercial diets were fasted, 20% of the activity was expressed. Fasted animals on the semi-purified diet also increased the per cent of expressed reductase activity, but this increase was not as great (13.3%). These data suggest that, in the rat, regulation of cholesterol synthesis in response to decreased total HMGR during fasting and increased levels after a meal results from alterations in the percentage of enzyme which is expressed. The semi-purified diet used here resulted in consistently lower levels of HMG-CoA reductase activity than the commercial diet regardless of feeding pattern.
mesh_terms: D000818:Animals; D002784:Cholesterol / Q000097:blood / Q000378:metabolism; D004032:Diet; D005215:Fasting; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism*; D008099:Liver / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000097:blood / Q000378:metabolism
chemical_list: D014280:Triglycerides; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases