NEUROTROPHIN-3 AUGMENTS STEROID-SECRETION BY HAMSTER OVARIAN FOLLICLES IN-VITRO

Innervation of the ovary is known to be affected by neurotrophic facto rs; mRNA for some of these molecules and their low-affinity receptors have been identified in ovarian follicular tissue. We attempted to det ermine whether neurotrophin (NT-3) exerts a non-neuronal impact on the ovary, affecting follicular estradiol secretion via a possible humora l action. Ovaries were excised from mature Golden Syrian Hamsters (Mes ocricetus auratus) and large preovulatory follicles were removed by mi crodissection. Follicles were incubated for 72 hr in control medium, o r medium containing 10 ng, 100 ng, or 1000 ng/ml NT-3. After culture, medium samples were assayed for estradiol content. NT-3 exerted dichot omous effects, depending on concentration: NT-3 augmented mean estradi ol output two-fold at 100 ng/ml, while 1000 ng/ml NT-3 decreased estra diol secretion back to control levels. By 48-72 hr in culture, all gro ups exhibited a significant decline in mean estradiol secretion due pr esumably to diminished viability, independent of neurotrophin action. These data suggest a humoral role for NT-3 in estradiol secretion of p reovulatory follicles in culture.