Dietary cholesterol fails to stimulate acylcoenzyme A: cholesterol acyltransferase activity in the liver of hamsters with a spontaneous high level of cholesterol.
The effect of exogenous cholesterol on acylcoenzyme A:cholesterol acyltransferase (ACAT) was investigated in conventional golden hamsters (NH) and in FEC hamsters characterized by a high level of cholesterol esters in the liver. ACAT activity was determined in liver microsomal fractions obtained from control animals, in animals fed 0.1% cholesterol diet or in microsomes preincubated with exogenous cholesterol. NH responded to cholesterol feeding by increasing the rate of cholesterol esterification in the liver, and exposure of the NH microsomes to media containing cholesterol stimulated ACAT activity. By comparison, whatever the conditions, cholesterol failed to alter the rate of cholesterol esterification in FEC hamsters. This finding raises several questions about cholesterol metabolism in the liver of these animals that does not fit into the well-established schemes of hepatic cholesterol metabolism.
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Institut de Physiologie, Université Paul-Sabatier CNRS, Toulouse, France.
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D000818:Animals; D002784:Cholesterol / Q000032:analysis / Q000494:pharmacology; D002788:Cholesterol Esters / Q000096:biosynthesis; D002791:Cholesterol, Dietary / Q000494:pharmacology*; D015243:Cholesterol, VLDL / Q000097:blood; D006224:Cricetinae; D004789:Enzyme Activation / Q000187:drug effects; D006937:Hypercholesterolemia / Q000201:enzymology* / Q000235:genetics; D008074:Lipoproteins / Q000097:blood; D008297:Male; D008647:Mesocricetus / Q000235:genetics / Q000378:metabolism*; D008862:Microsomes, Liver / Q000737:chemistry / Q000201:enzymology*; D013045:Species Specificity; D002785:Sterol O-Acyltransferase / Q000378:metabolism*
D002788:Cholesterol Esters; D002791:Cholesterol, Dietary; D015243:Cholesterol, VLDL; D008074:Lipoproteins; D002784:Cholesterol; D002785:Sterol O-Acyltransferase