Upregulation of adamts9 by gonadotropin in preovulatory follicles of zebrafish.

Previously we had identified adamts9 as a downstream target of Pgr, which is essential for ovulation in zebrafish. The primary goal of this study is to determine whether human chorionic gonadotropin (hCG, LH analog) also regulate adamts9 expression prior to ovulation. The expression of adamts9 was induced by hCG in a dose and time dependent manner in zebrafish preovulatory follicles in vitro. Interestingly, the stimulatory effect of hCG on adamts9 expression was not blocked in pgr-/- follicles but blocked in lhcgr-/-. This effect of hCG was via Lhcgr and its associated cAMP and PKC signaling pathways. Reduced fecundity and reduced expression of adamts9 were also found in lhcgr-/- females in vivo. Therefore, we have provided the first evidence of gonadotropin (hCG) regulated adamts9 in zebrafish, which could be important for ovulation.