Increased Progesterone Secretion and 3β-Hydroxysteroid Dehydrogenase Activity in Human Cumulus Cells by Pregnenolone Is Limited to the High Steroidogenic Active Cumuli

摘要

>Purpose: Several reports imply that lower progesteronesecretion by cumulus-oocyte complexes (COCs) isassociated with lower fertilization in the corresponding oocyte.The possible role of progesterone in oocyte fertilization inhumans was studied using two approaches: (a) increasingthe total progesterone secretion by culturing more than oneCOC per dish; and (b) increasing the cumulus cell progesterone secretion by providing pregnenolone as a substrate.>Methods: Mature COCs were cultured individually orcocultured in groups. Oocyte fertilization and progesteronesecretion were tested after 20 hr and 3 days in culture, respectively.The cumuli from individually plated COCs were cultured inthe absence of oocyte for an additional 3 days in order totest the effects of pregnenolone on progesterone secretionand the 3β-hydroxysteroid dehydrogenase (3β-HSD)activity. A comparable study with pregnenolone was performedon the corresponding granulosa-lutein cells.>Results: Increasing the number of COC to two instead ofone led to a significant increase in both fertilization rateand progesterone secretion. The addition of pregnenoloneduring days 3–6 increased significantly both progesteronesecretion and 3β-HSD activity. Comparable results wereobserved in granulosa-lutein cells subjected to pregnenolonetreatment. Following the first 3 days culture, cumulus masseswere categorized as secreting high or low progesteronelevels. Adding pregnenolone had a greater effect on bothprogesterone secretion and 3β-HSD activity in thehigh-progesterone-secreting cumuli.>Conclusions: Addition of pregnenolone increased progesterone secretion and 3β-HSD more efficiently in thehigher-progesterone-secreting cumuli. Coculture of two COCsinstead of one led to a higher fertilization rate and greaterprogesterone secretion.