The effects of mGnRH and cGnRH Ⅱ on the synthesis and secretion of LH and FSH of pituitary of Rana rugulosa during pre breeding stage were studied in vivo and in vitro. In vivo both mGnRH and cGnRH Ⅱ very significantly stimulated the release of LH and FSH from the pituitary of female and male. They also significantly elevated the LH levels of pituitary of female

but had no notable effects on LH or FSH content of pituitary of male. The FSH content of pituitary of female was also very significantly elevated by cGnRH Ⅱ. mGnRH was more effective than cGnRH Ⅱ in stimulating the LH synthesis and release of pituitary of female

or the FSH release of pituitary of male. In vitro both mGnRH at the dose of 0.1 ng/mL and cGnRH Ⅱ at the dose of 1 ng/mL very remarkably stimulated LH release from the incubated pituitary fragments of female.