细胞色素P-450（17α，裂解酶）介导的牛肾上腺皮质培养细胞雄激素合成途径。

Cytochrome P-450(17 alpha,lyase)-mediating pathway of androgen synthesis in bovine adrenocortical cultured cells.

作者信息

Yamazaki T, Nawa K, Kominami S, Takemori S

机构信息

Faculty of Integrated Arts and Sciences, Hiroshima University, Japan.

出版信息

Biochim Biophys Acta. 1992 Mar 16;1134(2):143-8. doi: 10.1016/0167-4889(92)90037-c.

DOI:10.1016/0167-4889(92)90037-c

PMID:1313302

Abstract

Cytochrome P-450(17 alpha,lyase) mediating pathway of dehydroepiandrosterone (DHA) formation from pregnenolone was investigated in primary cultures of bovine adrenocortical fasciculata-reticularis cells. To determine whether DHA formation proceeds predominantly by successive monooxygenase reactions without 17 alpha-hydroxypregnenolone leaving P-450(17 alpha,lyase) the cells were incubated with [14C]pregnenolone and 17 alpha-[3H]hydroxypregnenolone in the presence of Trilostane. Results of the double-substrate double-label experiments indicate that in the presence of high concentration of pregnenolone most of DHA was formed, directly from pregnenolone by the successive reactions. Since the concentration of pregnenolone usually exceeds that of 17 alpha-hydroxypregnenolone in the adrenal glands, DHA is concluded to be formed predominantly by successive reactions from pregnenolone without 17 alpha-hydroxypregnenolone leaving P-450(17 alpha,lyase) in vivo. By chronic ACTH treatment, the activities of 17 alpha-hydroxylation and DHA formation in adrenocortical cultured cells became higher concomitantly with the increase of P-450(17 alpha,lyase) content. Most of DHA was found to be formed by successive reactions from pregnenolone even under such conditions.

摘要

在牛肾上腺皮质束状带-网状带细胞原代培养物中，研究了细胞色素P-450（17α，裂解酶）介导孕烯醇酮生成脱氢表雄酮（DHA）的途径。为了确定DHA的形成是否主要通过连续的单加氧酶反应进行，且17α-羟基孕烯醇酮不会离开P-450（17α，裂解酶），在曲洛司坦存在的情况下，将细胞与[14C]孕烯醇酮和17α-[3H]羟基孕烯醇酮一起孵育。双底物双标记实验结果表明，在高浓度孕烯醇酮存在的情况下，大部分DHA是通过连续反应直接由孕烯醇酮形成的。由于肾上腺中孕烯醇酮的浓度通常超过17α-羟基孕烯醇酮的浓度，因此得出结论，在体内DHA主要由孕烯醇酮通过连续反应形成，且17α-羟基孕烯醇酮不会离开P-450（17α，裂解酶）。通过长期促肾上腺皮质激素（ACTH）处理，肾上腺皮质培养细胞中17α-羟化和DHA形成的活性随着P-450（17α，裂解酶）含量的增加而同时升高。即使在这种情况下，也发现大部分DHA是由孕烯醇酮通过连续反应形成的。