Intrinsic and extrinsic factors influencing steroid production in vitro by bovine follicles

摘要: Abstract Nonatretic bovine follicles were cultured on grids in a conventional static system, roller tubes or continuous flux system. Culture medium from the and tube system was replaced after 24 h of culture, while only small sample taken aseptically at that time. Steroid concentrations these samples estimated by radioimmunoassay (RIA) related to intrinsic factors like follicle size, day cycle micromorphological appearance end culture extrinsic O 2 -concentration applied gasphase time culture. Bovine nonatretic 8 mm showed same amount estradiol-17β (E2) production as pmol mg protein −1 h. Follicles over had significantly higher E2 production. follicular phase produced more than luteal phase, independent size Degeneration during resulted, decline E2-production, an increase P4-production; whereas T-production initially (primary atresia) rose but subsequently (secondary tertiary declined. The difference between systems reflected quantitative differences steroids measured. most striking one hand rolling other is predominant former every follicle. It thought this might be caused better 02 supply This hypothesis tested resulted P4, testosterone not decreased.