Effects of IGF1 and IGF2 on In Vitro Ovarian Follicle Maturation in Rainbow Trout, Oncorhynchus mykiss

Ovarian follicle maturation (OFM), including the resumption of meiosis in oocyte, is under hormonal regulation. Insulin-like growth factors (IGF) have been shown to participate regulation OFM with species-specific actions teleost fishes. In present study, vitro treatment rainbow trout ovarian follicles recombinant human insulin-like factor-1 (rhIGF1) or rhIGF2 did not induce germinal vesicle breakdown (GVBD), a marker for meiosis, oocytes. Co-incubation follicle-enclosed oocytes rhIGF1 and maturation-inducing steroid (MIS) trout, 17α,20β-dihydroxy-4-pregnen-3-one (17,20βP), also GVBD from that were able respond MIS alone suggesting IGFs cannot oocyte maturational competence (OMC), which ability MIS. Nevertheless, addition increased proportion completing compared alone, although this potentiation was small varied greatly among clutches fish at different stages migration. Collectively, these observations suggest may synergistic but directly are potent inducers OMC trout. Rainbow first found neither nor vitro.