[Difference of steroidogenesis in human ovary at different stage of cycle (author's transl)]

This experiment was undertaken to compare the steroidogenesis in human ovary at different stage of the cycle. Fifteen subjects, 8 in follicular, 7 in luteal phase were selected for this study. On hysterectomy, both ovarian and peripheral venous blood were collected simultaneously and follicle or corpus luteum were obtained. Steroid levels including pregnenolone(P5) 17 alpha-OH-P5, DHA, androstenediol (AD), progesterone(P4), 17 alpha-OH-P5, androstenedione(delta 4A) and testosterone(T) were measured by radioimmunoassay. Tissue were homogenized and incubated with labeled P5, 17 alpha-OH-P5, DHA and AD in the presence of NAD t 37 degrees C. As gas phase, CO was used. Metabolites were extracted and separated by TLC. 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) activity was expressed as the amounts of delta 4-steroid formed from corresponding delta 5 substrate. The levels of P5, P4, 17 alpha-OH-P4, DHA, delta 4A, T in the ovarian vein and the concentration of P5, 17 alpha-OH-P5, DHA, P4, 17 alpha-OH-P4, T in the ovarian tissue obtained in luteal phase were significantly higher than that in follicular phase. The results suggested that the delta 5 pathway seem to be active in corpus luteum. In follicular phase, highest concentration of 17 alpha-OH-P5 among delta 5 in ovarian vein and 17 alpha-OH-P4 among delta 4 steroid in ovarian vein and tissue was noticed. 3-beta-HSD activity was lower in follicle than that in corpus luteum. Substrate specificity was noticed in 3 beta-HSD in follicle and it was found that 17 alpha-OH-P5 seemed to be the most potent substrate for the enzyme. The difference of steroidogenesis between follicular and luteal phase was demonstrated in human ovary.