EFFECT OF HUMAN CHORIONIC-GONADOTROPIN AND PROLACTIN ON 20 ALPHA-HYDROXYSTEROID DEHYDROGENASE-ACTIVITY IN GRANULOSA-CELLS OF IMMATURE RAT OVARY

The effects of FSH, hCG, and PRL on the activity of 20α-hydroxysteroid dehydrogenase (20α-SDH) of separate ovarian components of hypophysectomized, diethylstilbestroltreated rats were studied. Enzyme activity was found to reside mainly in granulosa cells. FSH induced an increase in enzyme activity. A preparation of FSH was purified by adsorbing its LH contamination on rat corpora lutea membranes and by further neutralizing LH traces with an antiserum to the β-subunit of LH. This purified FSH retained the ability to induce a 6-fold increase in specific enzyme activity in granulosa cells of hypophysectomized, diethylstilbestrol-treated rats. Administration of hCG to rats treated with purified FSH, further enhanced 20α- SDH activity in granulosa cells up to 11.5-fold above control. PRL, which is known to inhibit 20α-SDH activity in regressing rat corpora lutea, suppressed the FSH-induced increase in enzyme activity in the granulosa cells. © 1979 by The Endocrine Society.