Abstract
Effects of HCG and prolactin on the activities of Δ5-3β-hydroxysteroid dehydrogenase (HSD), 17β-HSD and 20α-HSD in pronuclear hamster eggs were histochemically observed in vitro. When eggs were immersed in one of the solutions, each containing 5 i.u., 50 i.u. or 100 i.u. of HCG, the activities of Δ5-3β-HSD with dehydroepiandrosterone (DHA) or pregnenolone as the substrate, 17β-HSD with testosterone, and 20α-HSD with 20a-hydroxyprogesterone, were stimulated: the more was the amount of HCG in the solution, the stronger the activity was. With estradio1-17β as the substrate, the activity of 17β-HSD was not stimulated. Immersed in a solution containing either 5 i.u., 50 i.u. or 100 i.u. of prolactin, the activities of 17β-HSD with testosterone as the substrate and 20α-HSD with 20α-hydroxyprogesterone were stimulated: the more was the amount of prolactin in the solu-tion, the stronger the activity got. The activities of Δ5-3β-HSD with DHA or pregnenolone as the substrate, and 17β-HSD with estradiol-17β, were not stimulated.
