Failure of caloric restriction to influence cholesterol synthesis in hamsters fed identical amounts of dietary cholesterol

• Published in: Nutrition research (New York, N.Y.) Vol. 9; no. 2; pp. 217 - 226
• Main Authors: Jones, Peter J.H., Ridgen, Julie E.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 1989; Elsevier Science
• Subjects: actividad enzimatica; activite enzymatique; Biological and medical sciences; biosintesis; biosynthese; biosynthesis; Caloric Restriction; calorific value; Cholesterol; colesterol; cytoplasmic organelles; diet; dieta; enzymic activity; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; hamster; hamsters; HMG-CoA Reductase; organite cellulaire; organulos citoplasmaticos; oxidoreductases; oxidorreductasas; oxydoreductase; regime alimentaire; Synthesis; valeur calorique; valor calorico; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Synthesis; Caloric Restriction; Cholesterol; HMG-CoA Reductase; Calorie; Plasma; Duodenum; Nutrition; Enzyme; Liver; Body weight; Rodentia; Biosynthesis; Microsome; Metabolism; Small intestine; Restriction modification; Vertebrata; Mammalia; Energy; Diet; Hamster
• ISSN: 0271-5317; 1879-0739
• DOI: 10.1016/S0271-5317(89)80008-9

To examine the effect of caloric restriction on cholesterol metabolism, independent of cholesterol intake, 3 groups of male Syrian hamsters were fed synthetic diets either ad libitum (AL) or pair-fed at 75% (R-75) and 50% (R-50) of ad libitum intake. Cholesterol intake of each group was 4.0±0.2 mg/day. On diet day 10 in each group, plasma cholesterol levels were measured and liver and duodenal 3H incorporation into digitonin precipitable sterols determined 90 min after intravenously injected 3H 2O. Microsomal 3-hydroxyl-3-methylglutaryl-coenzyme-A (HMG-CoA) reductase activities were also measured in liver and duodenum. Body weights on day 10 for AL (115.8±7.2 g, x±SD), R-75 (107.7±6.3 g) and R-50 (99.6±3.0 g) groups decreased significantly with increasing severity of caloric restriction (p<0.05). Percent body fat and liver weights were also lower in caloric restricted groups. No differences were observed in plasma cholesterol concentrations (163±12, 151±10, 152±15 mg/dl, for AL, R-75 and R-50, respectively) or in the rate of 3H 2O incorporation into cholesterol either in liver (17.7±4.1, 11.9±1.6, 13.5±6.8 nmol 3H 2O/hr *mg tiss chol., x±SEM) or in duodenum (86.0±11.3, 97.6±9.4, 103.7±18.3 3H 2O/hr *mg tiss chol.). Moreover, liver and duodenal HMG-CoA reductase activites were not different between feeding groups. These data suggest that the mechanisms of regulation of cholesterol synthesis are insensitive to alterations in energy substrate flux induced by caloric restriction.