[The role of gonadotropins, cyclic AMP, 22-R-hydroxycholesterol and cofactors in regulating endocrine functions of the Leydig cells in rats. II. Effects of LH, hCG, dbcAMP, 22-R-OH-cholesterol and cofactors on the synthesis of pregnenolone and testosterone in the interstitial gland of rats].

The authors examined in vitro the influence of gonadotrophins, cAMP, 22-R-OH-cholesterol and cofactors on the synthesis of pregnenolon and testosterone in the interstitial gland of the rat. Sections of the nucleus were incubated with LH (100 ng/ml), hCG (1.0 j.m./ml), dbcAMP (1 mM), 22-R-OH-cholesterol (30 microM) and cofactors (NAD + NADP + G-6-P + G-6-PDH). It was found that an increase in concentrations of hCG above physiological values was not accompanied by an increase in secreting steroid hormones. LH, hCG and dbcAMP increased the synthesis of pregnenolon twice, and testosterone--three times. 22-R-OH-cholesterol as a substrate increased the synthesis three and four times respectively, and added cofactors five times and four and a half times respectively. Joining 22-R-OH-cholesterol or a cofactor with LH does not intensify a stimulating effect.