The in vitro catabolism of cholesterol: a comparison of the formation of cholest-4-en-7-alpha-ol-3-one and 5-beta-cholestan-7-alpha-ol-3-one from cholesterol in rat liver
Mendelsohn, D.; Mendelsohn, L.; Staple, E.
Biochemistry 5(4): 1286-1290
1966
ISSN/ISBN: 0006-2960
PMID: 5958203
DOI: 10.1021/bi00868a023
Accession: 068623958
The enzymatic conversion of cholesterol to 7[alpha]-hydroxycholest-4-en-3-one and 7[alpha]-hydroxy-5[beta]-cholestan-3-one has been studied using a preparation from rat liver in vitro. The data demonstrate that rat liver is able to metabolize cholesterol to 7[alpha]-hydroxycholest-4-en-3-one but not to 7[alpha]-hydroxy-5[beta]-cholestan-3-one. It is suggested that 7[alpha]-hydroxycholest-4-en-3-one is probably an intermediate onthe cholesterol to bile acid metabolic pathway. The results also provide indirect evidence that epimerization of the 3[beta]-hydroxyl group of cholesterol to the [alpha] configuration may occur via ketone formation at position C-3 and, furthermore, that the [DELTA] 5 double bond of cholesterol may be isomerized to the [DELTA]4 position before being reduced. A tentative scheme of the early stages in bile acid formation from cholesterol in rat liver has been presented.