홍바리(Epinephelus fasciatus) 난황형성기 난모세포에서의 성호르몬 대사

Abstract

We studied oocyte steroidogenesis by blacktip grouper, Epinephelus fasciatus ovarian follicles during vitellogenesis. Vitellogenic oocytes with average diameters of 0.45, 0.48 and 0.50 mm were used for the studies and were incubated in vitro in the presence of [3H]17α-hydroxyprogesterone as a precursor. The steroid metabolites were analyzed using a thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC/MS). The major metabolites were androstenedione (A4), testosterone (T), estradiol-17β (E2) and estrone (E1) in vitellogenic oocytes. The metabolite of A4 was increased at the oocytes of 0.50 mm, while that of E1 was decreased. The metabolite of E2 was lower in the oocytes of 0.50 mm than that in the oocytes of 0.48 mm. These results suggest that the oocytes with average diameter of 0.50 mm are fully vitellogenic stage in blacktip grouper. Interestingly, the metabolic pattern of E1 was similar to E2 in tested oocytes. Previous studies have demonstrated that E2 is synthesized via E1 in some hermaphrodite species. However, it is still unknown whether the E1-E2 pathway is conserved in blacktip grouper. Future studies should examine the roles of E1 during vitellogenesis in this species.