EXOGENOUSLY HYPERCHOLESTEROLEMIC RATS, COMPARED WITH THEIR PROGENITORSPRAGUE-DAWLEY RATS, HAVE ALTERED MESSENGER-RNAS FOR CHOLESTEROL 7-ALPHA-HYDROXYLASE AND LOW-DENSITY-LIPOPROTEIN RECEPTOR AND ACTIVITIES OFCHOLESTEROL 7-ALPHA-HYDROXYLASE AND ACYL-COA - CHOLESTEROL ACYLTRANSFERASE IN THE LIVER IN RESPONSE TO DIETARY-CHOLESTEROL
K. Nagao et al., EXOGENOUSLY HYPERCHOLESTEROLEMIC RATS, COMPARED WITH THEIR PROGENITORSPRAGUE-DAWLEY RATS, HAVE ALTERED MESSENGER-RNAS FOR CHOLESTEROL 7-ALPHA-HYDROXYLASE AND LOW-DENSITY-LIPOPROTEIN RECEPTOR AND ACTIVITIES OFCHOLESTEROL 7-ALPHA-HYDROXYLASE AND ACYL-COA - CHOLESTEROL ACYLTRANSFERASE IN THE LIVER IN RESPONSE TO DIETARY-CHOLESTEROL, Comparative biochemistry and physiology. B. Comparative biochemistry, 118(4), 1997, pp. 949-955
Exogenously hypercholesterolemic (ExHC) rats promptly increase serum c
holesterol concentration in response to dietary cholesterol. To examin
e underlying mechanism(s) for this susceptibility, responses of mRNAs
for cholesterol metabolism-related proteins and their activities in th
e liver to dietary cholesterol were compared between ExHC rats and the
ir progenitor Sprague Dawley rats. ExHC rats slightly decreased the ab
undance of low density lipoprotein (LDL) receptor mRNA in response to
dietary cholesterol, although the amount of LDL receptor was not influ
enced. The abundance of cholesterol 7 alpha-hydroxylase mRNA and the e
nzyme activity in response to dietary cholesterol were greater in ExHC
rats, but the fecal excretion of bile acid was comparable between the
strain. Dietary cholesterol-dependent elevation of acyl-CoA:cholester
ol acyltransferase activity was greater in ExHC rats. The concentratio
n of liver triacylglycerols was markedly lower in ExHC rats. These res
ults suggest that ExHC rats may increase serum cholesterol by increasi
ng hepatic secretion of cholesteryl ester-rich particles. (C) 1997 Els
evier Science Inc.