| Abstract: | ![]()
Hormonal regulation in the expression of CYP2C27, a male-predominant form of cytochrome P450 in the hamster, was investigated. The mRNA level of CYP2C27 was five-fold higher in male than in female livers. The mRNA level was suppressed by both gonadectomy and hypophysectomy in male, while the mRNA level was increased by the same treatment in female, resulting in the disappearance of sex difference. In both sexes, treatment of the gonadectomized animals with testosterone induced the cytochrome over the level of shamoperated males. Treatment of the hypophysectomized animals with testosterone elevated the level in females. On the other hand, oestradiol did not show any effects on either the gonadectomized or the hypophysectomized animals of both sexes. Twice-daily injection of growth hormone to hypophysectomized animals restored the level in males. Continuous infusion of growth hormone to hypophysectomized animals suppressed the level in both sexes. These results indicate that the expression of CYP2C27 in hamsters is under the control of endocrine factors and suggest that the gonadal-pituitary axis pathway is a control mechanism as proposed in rats and mice. |
