The role of age on the cholesterol-metabolizing enzymes and lipid levels in chick plasma and liver microsomes after cholesterol enriched diet cessation.
Chicks of two age groups (11 and 21 days-old) were fed a cholesterol enriched diet administered either from hatching or for only 6 hours (9:00-15:00). Afterwards, the cholesterol was removed from the diet and we analysed hepatic Acyl-coenzyme A:cholesterol acyltransferase (ACAT) and 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase activities, plasma cholesterol levels and hepatic microsomal cholesterol content up to a day and a half. The treatments raised plasma and microsomal cholesterol levels in both age groups, increases in the older group exceeding those of the younger chicks. After removal of the cholesterol diet, both groups recovered by the middle of the next day, reaching values similar to those of control-chick groups. The ACAT activity showed a relationship with the microsomal cholesterol levels although did not return to similar levels than those of control microsomes. This correlation was not observed in HMG-CoA reductase. In general, differences in returning to the control values depended on the developmental stage of the chick.
Department of Biochemistry and Molecular Biology, Faculty of Sciences, University of Granada, Spain.
J L
JL
Segovia
M
M
García-González
M J
MJ
Alejandre
D000214:Acyl Coenzyme A / Q000378:metabolism; D000375:Aging / Q000378:metabolism*; D000818:Animals; D002645:Chickens; D002784:Cholesterol / Q000097:blood / Q000378:metabolism*; D002791:Cholesterol, Dietary / Q000008:administration & dosage*; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology* / Q000378:metabolism; D002785:Sterol O-Acyltransferase / Q000378:metabolism
D000214:Acyl Coenzyme A; D002791:Cholesterol, Dietary; D008055:Lipids; C008047:3-hydroxy-3-methylglutaryl-coenzyme A; D002784:Cholesterol; D002785:Sterol O-Acyltransferase