REGULATION OF CYTOCHROME P-450

大鼠致癌物诱导型和组成型的表达调控 检测细胞色素P-450。组织特异性反应3- 甲基胆蒽（MC）治疗的免疫化学探测， 抗P-450 c抗体，并通过芳香烃羟化酶酶促 (AHH)活动大鼠组织匀浆中P450 c水平降低， 依次为：肝、鼻咽、肺、胰、肾。P-450 c的水平 和AHH没有相关性，表明肝外AHH活性 显著来源于除P-450 c以外的P450形式，和/或 P-450 c的比活性在不同组织中不同。感应 2-乙酰氨基芴对大鼠肝微粒体和核膜P450的影响 (AAF)检查MC。P-450 c和P-450 d在细胞中的诱导差异 微粒体和核膜。此外该 抗氧化剂丁基化羟基甲苯加强P450 c的AAF诱导。 老化对几种睾酮羟化P-450的影响是 研究了24个月大的大鼠P-450 a及其受体水平升高， 相关的7 α-羟化酶活性，但其他几种 羟化酶活性因此，尽管P-450催化活性通常 随着年龄的增长，个别P-450的表达被选择性抑制， 或激活。

The regulation of expression of rat carcinogen-inducible and constitutive cytochromes P-450 was examined. The tissue specific response to 3- methylcholanthrene (MC) treatment was probed both immunochemically with antibodies to P-450c, and enzymatically by aryl hydrocarbon hydroxylase (AHH) activity. The level of P450c in rat tissue homogenates decreased in the order: liver, nasopharynx, lung, pancreas, kidney. The levels of P-450c and AHH did not correlate, indicating that extrahepatic AHH activity significantly derives from P450 forms other than P-450c, and/or the specific activity of P-450c varies among different tissues. The induction of rat liver microsomal and nuclear envelope P450s by 2-acetylaminofluorene (AAF) and MC was examined. P-450c and P-450d were differentially induced in microsomes and nuclear envelopes by each agent. In addition, the antioxidant butylated hydroxytoluene accentuated AAF induction of P450c. The effect of aging on several testosterone-hydroxylating P-450s was studied. Twenty-four month old rats had elevated levels of P-450a and its associated 7alpha-hydroxylase activity, but lower levels of several other hydroxylase activities. Thus, although P-450 catalyzed activities generally decline with age, expression of individual P-450s are selectively repressed or activated.