雌二醇在食用蛙（Rana esculenta）睾丸中局部反馈机制的作用位点。

Sites of action of local estradiol feedback mechanism in the frog (Rana esculenta) testis.

作者信息

Fasano S, D'Antonio M, Pierantoni R

机构信息

Dipartimento di Fisiologia Umana e Funzioni Biologiche Integrate F. Bottazzi, I Facoltà di Medicina e Chirurgia, Università di Napoli, Italy.

出版信息

Gen Comp Endocrinol. 1991 Mar;81(3):492-9. doi: 10.1016/0016-6480(91)90177-8.

DOI:10.1016/0016-6480(91)90177-8

PMID:2055446

Abstract

The direct effect of estradiol on testicular androgen biosynthesis was studied in the frog, Rana esculenta, measuring progesterone, 17 alpha-OH-progesterone, androstenedione, and androgens (T + DHT) in supernatants and testes incubated (6 hr, 15 degrees) with estradiol alone (10(-6) M) or in combination with crude pituitary homogenate (1 pituitary equivalent/tube). Estradiol, either alone or in combination with pituitary homogenate, induced decreases of 17 alpha-OH-progesterone, androstenedione, and androgens but was ineffective in modulating progesterone levels. Pituitary homogenate was effective in inducing a significant increase of androstenedione and androgens but was ineffective in modulating both progesterone and 17 alpha-OH-progesterone production. It is concluded that estradiol acts by decreasing the activity of steroidogenic enzymes starting from 17 alpha-hydroxylase, while pituitary homogenate does not affect the 17 alpha-hydroxylase activity, but it acts starting from 17,20-lyase.

摘要

在食用蛙（Rana esculenta）中研究了雌二醇对睾丸雄激素生物合成的直接影响，通过测量单独用雌二醇（10⁻⁶ M）或与粗制垂体匀浆（每管1个垂体当量）一起孵育（6小时，15摄氏度）的上清液和睾丸中的孕酮、17α-羟基孕酮、雄烯二酮及雄激素（睾酮+双氢睾酮）。单独的雌二醇或与垂体匀浆联合使用时，均可使17α-羟基孕酮、雄烯二酮及雄激素水平降低，但对孕酮水平的调节无效。垂体匀浆可有效诱导雄烯二酮和雄激素显著增加，但对孕酮和17α-羟基孕酮的产生调节无效。研究得出结论，雌二醇通过降低从17α-羟化酶开始的类固醇生成酶的活性起作用，而垂体匀浆不影响17α-羟化酶活性，但从17,20-裂解酶开始起作用。