Estradiol-17β interference with meiotic maturation inRana pipiens ovarian follicles: Evidence for inhibition of 3β-hydroxysteroid dehydrogenase
✍ Scribed by Spiegel, Judith ;Jones, Elizabeth ;Snyder, B. W.
- Publisher
- John Wiley and Sons
- Year
- 1978
- Tongue
- English
- Weight
- 364 KB
- Volume
- 204
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
Increasing doses of estradiol‐17β added to in vitro incubations inhibited pregnenolone‐induced germinal vesicle breakdown in Rana pipiens ovarian follicles. The inhibition was reversed with increasing concentrations of pregnenolone added to the medium. Because no evidence of estradiol‐17β inhibition or interaction with progesterone‐induced GVBD was observed, the effect of estradiol‐17β on the conversion of ^3^H‐pregnenolone to ^3^H‐progesterone was investigated. Estradiol‐17β in doses as low as 10^−7^ M significantly inhibited the conversion of ^3^H‐pregnenolone to ^3^H‐progesterone in follicles incubated in vitro. It is suggested that estradiol‐17β is a feedback inhibitor of 3β‐hydroxysteroid dehydrogenase‐isomerase, the enzyme complex that converts pregnenolone to progesterone, a necessary step in the initiation of GVBD.