Dietary fatty acids regulate cholesterol induction of liver CYP7alpha1 expression and bile acid production.
In the present study we investigated the effects of dietary fats containing predominantly PUFA, monounsaturated FA (MUFA), or saturated FA (SFA) on lipid profile and liver cholesterol 7alpha-hydroxylase (CYP7alpha1) mRNA expression and bile acid production in C57BL/6J mice. The animals (n = 75) were randomly divided into five groups and fed a basic chow diet (AIN-93G) (BC diet), a chow diet with 1 g/100 g of cholesterol (Chol diet), a chow diet with 1 g/100 g of cholesterol and 14 g/100 g of safflower oil (Chol + PUFA diet), a chow diet with 1 g/100 g of cholesterol and olive oil (Chol + MUFA diet), or a chow diet with 1 g/100 g of cholesterol and myristic acid (Chol + SFA diet) for 6 wk. The results showed that the Chol + SFA diet decreased CYP7alpha1 gene expression and bile acid pool size, resulting in increased blood and liver cholesterol levels. Addition of PUFA and MUFA to a 1% cholesterol diet increased the bile acid pool production or bile acid excretion and simultaneously decreased liver cholesterol accumulation despite decreased CYP7alpha1 mRNA expression. The results indicate that the decreased bile acid pool size induced by the SFA diet is related to inhibition of the liver CYP7alpha1 gene expression, but an increased bile acid pool size and improved cholesterol homeostasis are disassociated from the liver CYP7alpha1 gene expression.
Li
Yan
Y
Department of Clinical Nutrition, Sun Yat-sen University Northern Campus, Guangzhou, 510080, People's Republic of China.
Hou
Meng Jun
MJ
Ma
Jing
J
Tang
Zhi Hong
ZH
Zhu
Hui Lian
HL
Ling
Wen Hua
WH
D000818:Animals; D001647:Bile Acids and Salts / Q000096:biosynthesis*; D002784:Cholesterol / Q000494:pharmacology*; D002790:Cholesterol 7-alpha-Hydroxylase / Q000096:biosynthesis*; D002791:Cholesterol, Dietary / Q000494:pharmacology; D004041:Dietary Fats / Q000494:pharmacology*; D005227:Fatty Acids / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D005260:Female; D008055:Lipids / Q000097:blood; D008099:Liver / Q000201:enzymology*; D051379:Mice; D008810:Mice, Inbred C57BL; D000069463:Olive Oil; D010938:Plant Oils / Q000494:pharmacology; D012450:Safflower Oil / Q000494:pharmacology
D001647:Bile Acids and Salts; D002791:Cholesterol, Dietary; D004041:Dietary Fats; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D008055:Lipids; D000069463:Olive Oil; D010938:Plant Oils; D012450:Safflower Oil; D002784:Cholesterol; D002790:Cholesterol 7-alpha-Hydroxylase; C502772:Cyp7a1 protein, mouse