GSBS Student Publications

Title

Cloning, expression, and regulation of lithocholic acid 6 beta-hydroxylase

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Biochemistry and Molecular Biology

Date

11-5-1991

Document Type

Article

Medical Subject Headings

Amino Acid Sequence; Animals; *Aryl Hydrocarbon Hydroxylases; Base Sequence; Blotting, Northern; Blotting, Southern; Cholic Acid; Cholic Acids; Cloning, Molecular; Cricetinae; Cytochrome P-450 Enzyme System; DNA; Enzyme Induction; Gene Expression Regulation; Genes; Lithocholic Acid; Liver; Molecular Sequence Data; RNA, Messenger; Restriction Mapping; Sequence Alignment; Steroid Hydroxylases; Transfection

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

We have isolated a hamster liver cDNA whose expression is induced upon feeding hamsters with a cholic acid-rich diet. It was identified as a cytochrome P450 family 3 protein, by sequence homology, and named CYP3A10. The activity of CYP3A10 was determined by transient expression of its cDNA in transfected COS cells and was found to hydroxylate lithocholic acid at position 6 beta. CYP3A10 RNA is 50-fold higher in males than in female hamsters. In males, it appears to be regulated by age with expression highest after puberty. Shortly after weaning (28 days), cholic acid feeding of male hamsters elevates the level of message over that of hamsters fed with normal laboratory chow. Females do not exhibit regulation by cholic acid. In hamster liver, murideoxycholic acid, the 6 beta-metabolite of lithocholic acid, is the major hydroxylated product of lithocholic acid. Lithocholic acid 6 beta-hydroxylase (6 beta-hydroxylase) activity is greatly diminished in hamster female liver microsomes as would be expected due to the lack of CYP3A10 mRNA in females. Additionally, male liver microsomal 6 beta-hydroxylase activity was increased by cholic acid feeding, consistent with the cholic acid-mediated induction of its RNA. These results indicate that, in male hamsters, 6 beta-hydroxylation is the major pathway for detoxification of lithocholate and that, likely, CYP3A10 is responsible for that activity.

Rights and Permissions

Citation: J Biol Chem. 1991 Nov 5;266(31):21030-6.

Related Resources

Link to Article in PubMed

Journal Title

The Journal of biological chemistry

PubMed ID

1840595