17α-Hydroxyprogesterone induced ovarian growth and vitellogenesis in the freshwater rice field crab Oziotelphusa senex senex

Vitellogenin, a female-specific phospholipoglycoprotein was used as one of the markers for detecting the induction of reproduction caused by exposure to exogenous chemicals. In the present study, we demonstrated the effect of 17α-hydroxyprogesterone on the induction of reproduction in the female crab, Oziotelphusa senex senex. The crabs were injected with 17α-hydroxyprogesterone at the doses of 10− 8 or 10− 7 mol/crab on 1st, 7th, 14th, 21st and 28th day of experiment. The mean oocyte diameter and mean ovarian indices in experimental females were increased significantly (p < 0.001) when compared with the initial controls. The ovarian vitellogenin content in the experimental females was also increased significantly (p < 0.001) in a dose-dependent manner when compared with the initial controls. The vitellogenin was purified and confirmed by double immunodiffusion with anti-vitellin–antisera raised against vitellogenin for this crab. From the results, it is clear that the 17α-hydroxyprogesterone induces ovarian growth and ovarian vitellogenin synthesis in the crab O. senex senex.