Expression of hepatic microsomal cholesterol 7 alpha-hydroxylase activity in lean and obese Zucker rats |
| |
| Authors: | P M Tang J A Finkelstein J Y Chiang |
| |
| Affiliation: | Department of Biochemistry and Molecular Pathology, Northeastern Ohio Universities College of Medicine, Rootstown 44272. |
| |
| Abstract: | The activity of hepatic microsomal cholesterol 7 alpha-hydroxylase was studied in genetically obese and lean Zucker rats. The liver microsomal cholesterol 7 alpha-hydroxylase activity in fatty Zucker rats (fa/fa) is about 50% to 70% lower than that of the lean (Fa/-) rats of the same sex, when animals were sacrificed at the middle of the dark cycle. When rats were sacrificed at the middle of the light cycle, cholesterol 7 alpha-hydroxylase activity was the same as in the dark cycle in obese rats of both sexes, but was 65% lower in lean rats. However, cholesterol 7 alpha-hydroxylase activity was stimulated by the treatment with cholestyramine in both obese and lean rats. Our results suggested that the diurnal regulation of cholesterol 7 alpha-hydroxylase activity is lost in obese rats but was present under cholestyramine treatment in the genetically obese strain of rats. |
| |
| Keywords: | |
|
|
