Regulation of Sex-Specific Forms of Cytochrome P-450 : Cytochrome P-450 in Liver Microsomes of Hamsters

三种形式的细胞色素P-450经SDS-PAGE纯化后均一。从雌性仓鼠肝微粒体中纯化的细胞色素P-450(P-450-fHS1)的一种形式，根据氧化形式的绝对光谱判断，主要以低自旋状态存在，并与抗P450雄性抗体发生交叉反应。根据与抗P-450雄性抗体的交叉反应，从雄性和雌性仓鼠的肝微粒体中提纯的其他形式的细胞色素P-450分别被暂定为P-450-mHS2和P-450-fHS2。P-450-mHS2在DEAE-5PW和羟基磷灰石柱上的层析行为与P-450-fHS2相同。从绝对光谱来看，两种细胞色素P-450主要处于低自旋态。比较前20个氨基酸序列，P-450-mHS2和P-450-fHS2的N-末端氨基酸序列完全相同。N-末端氨基酸序列为f-…与P-450-mHS2和P-450-fHS2的同源性达80%以上。用抗P-450-fHS1抗体对雄性仓鼠肝微粒体进行免疫印迹分析表明，与P-450-fHS1免疫化学相关的P-450-fHS1或细胞色素P-450也存在于雄性仓鼠的肝微粒体中。但P-450-FHS1在女性中的含量明显高于男性。相反，细胞色素P-450与抗P-450-mHS2抗体在雌性金黄地鼠微体中的交叉反应与雄性金黄地鼠微体中的含量相当。雌性仓鼠去性腺或给予睾酮后，肝微粒体中P-450-FHS1的含量降低。用睾酮处理去性腺的雌性仓鼠，但不用雌二醇处理，导致P-450-fHS1的数量进一步减少。另一方面，去性腺或雌激素处理对雄性仓鼠微粒体中与P-450-fHS1免疫化学相关的P-450-fHS1或细胞色素P-450的含量几乎没有影响，而去性腺的雄性金黄地鼠经雌二醇处理后，细胞色素P-450的含量增加。P-450-fHS2和P-450-fHS2对孕酮6β羟化均有活性，但对睾酮羟化无活性。P-450-fHS2在重建体系中催化氨基比林、苯丙胺和红霉素的N-脱甲基和7-乙氧基香豆素的O-脱甲基化。P-450-mHS2催化红霉素的N-脱甲基化和7-乙氧基香豆素的O-脱甲基化，但不能催化氨基比林和苯丙胺的N-脱甲基化。较少

Three forms of cytochrome P-450 were purified to electrophoretical homogeneity on SDS-PAGE. One of the forms of cytochrome P-450 (P-450-fHS1) purified from liver microsomes of female hamster was considered to be mainly present in a low spin state as judged by absolute spectrum of the oxidized form and was cross-reactive with anti-P450-male antibodies. Other forms of cytochrome P-450 Purified from liver microsomes of male and female hamsters according to the cross-reactivity with anti-P-450-male antibodies were tentatively termed P-450-mHS2 and P-450-fHS2, respectively. Chromatographic behavior of P-450-mHS2 on DEAE-5PW column and hydroxylapatite column were identical to those of P-450-fHS2. Judging from the absolute spectra, both cytochromes P-450 were shown to be mainly in low spin states. N-Terminal amino acid sequence of P-450-mHS2 was identical with that of P-450-fHS2 when the first 20 amino acid sequence was compared. In addition, N-terminal amino acid sequence of P-450-fHS2 was f … More ound to be 80% homologous to those of P-450-mHS2 and P-450-fHS2. Western blot analysis of liver microsomes of male hamsters with anti-P-450-fHS1 antibodies showed that P-450-fHS1 or cytochrome P-450 immunochemically related to P-450-fHS1 was also present in liver microsomes of male hamsters. However, the amounts of P-450-fHS1 was found to be much higher in female than male. On the contrary, the content of cytochrome P-450 cross-reactive with anti-P-450-mHS2 antibodies in female hamster microsomes was comparable to that in male hamster microsomes. The content of P-450-fHS1 in liver microsomes of female hamsters was decreased by gonadectomy of female hamsters or the administration of testosterone. Treatment of gonadectomized female hamsters with testosterone, but not with estradiol, resulted in further decrease in the amount of P-450-fHS1. On the other hand, the content of P-450-fHS1 or cytochrome P-450 immunochemically related to P-450-fHS1 in male hamster microsomes was virtually unaffected by gonadectomy or the treatment with estradiol whereas the content of the cytochrome P-450 was increased by the treatment of gonadectomized male hamsters with estradiol. Both P-450-fHS2 and P-450-fHS2 were active for 6beta-hydroxylation of progesterone but not for testosterone hydroxylation. P-450-fHS2 catalyzed N-demethylations of aminopyrine, benzphetamine and erythromycin, and O-deethylation of 7-ethoxycoumarin in a recontituted system. P-450-mHS2 catalyzed N-demethylation of erythromycin and O-deethylation 7-ethoxycoumarin but not N-demethylations of aminopyrine and benzphetamine. Less