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

在SDS-PAGE上将三种形式的细胞色素P-450纯化至电泳均一。从雌性仓鼠肝微粒体中纯化的细胞色素P-450（P-450-fHS 1）的一种形式被认为主要以低自旋状态存在，如通过氧化形式的绝对光谱所判断的，并且与抗P450-雄性抗体交叉反应。根据与抗P-450-雄性抗体的交叉反应性，从雄性和雌性仓鼠肝微粒体中纯化的其他形式的细胞色素P-450分别暂定为P-450-mHS 2和P-450-fHS 2。P-450-mHS 2在DEAE-5 PW柱和羟基磷灰石柱上的色谱行为与P-450-fHS 2相同。从绝对光谱判断，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-mHS 2和P-450-fHS 2的N-末端氨基酸序列完全相同。此外，P-450-fHS 2的N-末端氨基酸序列为： ...更多信息 与P-450-mHS 2和P-450-fHS 2同源性为80%。用抗P-450-fHS 1抗体对雄性仓鼠的肝微粒体进行Western印迹分析，结果表明，P-450-fHS 1或与P-450-fHS 1免疫化学相关的细胞色素P-450也存在于雄性仓鼠的肝微粒体中。然而，P-450-fHS 1的量被发现在女性中比男性高得多。相反，雌性仓鼠微粒体中与抗P-450-mHS 2抗体交叉反应的细胞色素P-450含量与雄性仓鼠微粒体中的细胞色素P-450含量相当。切除雌性仓鼠的性腺或给予睾酮可降低雌性仓鼠肝微粒体中P-450-fHS 1的含量。用睾酮而不是雌二醇处理性腺切除的雌性仓鼠，导致P-450-fHS 1的量进一步减少。另一方面，雄性仓鼠微粒体中P-450-fHS 1或与P-450-fHS 1免疫化学相关的细胞色素P-450的含量几乎不受性腺切除术或雌二醇治疗的影响，而细胞色素P-450的含量通过用雌二醇治疗性腺切除的雄性仓鼠而增加。P-450-fHS 2和P-450-fHS 2都对孕酮的6 β-羟基化有活性，但对睾酮羟基化无活性。P-450-fHS_2催化氨基比林、苄非他明和红霉素的N-脱甲基化反应和7-乙氧基香豆素的O-脱乙基化反应。P-450-mHS 2催化红霉素的N-脱甲基化和7-乙氧基香豆素的O-脱乙基化，但不催化氨基比林和苄非他明的N-脱甲基化。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