Dietary fat and cholesterol effects on cholesterol metabolism in CBA/J and C57BR/cdJ mice.
The aim of this study was to determine how small differences in dietary fats affect cholesterol metabolism in mice hypo- (CBA/J) and hyperresponsive (C57BR/cdJ) to diet-induced hypercholesterolemia. Six-wk-old male mice were fed either a diet corresponding to the U.S. average gross composition (US74, 40% of total energy as fat, 347 mg cholesterol/1000 Kcal, P/S = 0.24) or a modified-fat diet (30% of total energy as fat, 46 mg cholesterol/1000 Kcal, P/S = 0.91). After 8 wk of feeding, neither strain had developed hypercholesterolemia. CBA/J mice had higher concentrations of serum total and high-density lipoprotein (HDL) cholesterol and a higher esterified-to-free cholesterol ratio than did C57BR/cdJ mice. CBA/J mice maintained a constant serum cholesterol concentration mainly by adjusting the hepatic hydroxymethylglutaryl coenzyme A reductase (HMGR) activity, whereas C57BR/cdJ mice did so by changing the fecal excretion of cholesterol. Compared to the modified-fat diet, the US74 diet caused an increase in the ratio of total to HDL serum cholesterol, liver microsomal free cholesterol, fecal cholesterol and hepatic microsomal cholesterol 7 alpha-hydroxylase activity and a decrease in hepatic microsomal HMGR activity. We conclude that the metabolic responses to small differences in dietary fat are different in CBA/J and C57BR/cdJ mice.
Kuan
S I
SI
Department of Food and Nutrition, Iowa State University, Ames 50011.
Dupont
J
J
D000818:Animals; D002784:Cholesterol / Q000097:blood / Q000378:metabolism*; D002790:Cholesterol 7-alpha-Hydroxylase / Q000378:metabolism; D002791:Cholesterol, Dietary / Q000494:pharmacology*; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D005227:Fatty Acids / Q000008:administration & dosage; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage; D005243:Feces / Q000032:analysis; D005260:Female; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008862:Microsomes, Liver / Q000378:metabolism; D013045:Species Specificity
D002791:Cholesterol, Dietary; D004041:Dietary Fats; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases; D002790:Cholesterol 7-alpha-Hydroxylase