The effects of estrogen and progesterone on the growth of dysgerminoma of ovary heterotransplanted to ovariectomized athymic nude mice (OVX-NUs) were examined. OVX-NUs were divided into 6 groups and a subcutaneous injection of either 1 micrograms or 10 micrograms of estradiol (E1 or E10), 0.1 mg or