Abstract

Sex-related differences in the expression of cytochrome P450 isozymes in hamsters were investigated. Three distinct cDNA clones (assigned as CYP2C25, CYP2C26, and CYP2C27) were isolated from liver cDNA libraries from male and female hamsters, using rat CYP2C11 cDNA as a probe. Sequence analysis revealed that these three forms were very similar to each other (> 90% identity of nucleotide sequences) and belong to the CYP2C gene subfamily. The CYP2C25, CYP2C26, and CYP2C27 cDNA clones consisted of an open reading frame encoding 490 amino acids. CYP2C25, CYP2C26, and CYP2C27 proteins expressed in Saccharomyces cerevisiae catalyzed the hydroxylation of tolbutamide and the N-demethylation of aminopyrine and benzphetamine. Only CYP2C25 showed testosterone hydroxylase (16 beta) activity. Northern blot analyses with specific oligonucleotide probes demonstrated that expression of CYP2C27 was male specific and male predominant in kidneys and livers, respectively. No sex-related difference was observed in the expression of CYP2C25 and CYP2C26. These results support our previous findings that sex-related differences in the expression of liver microsomal cytochromes P450 occur in hamsters.