IN-VITRO FERTILIZING-CAPACITY OF SPERM FROM FSH-TREATED PHOTOINHIBITED DJUNGARIAN HAMSTERS (PHODOPUS-SUNGORUS)

In hypogonadal male Djungarian hamsters FSH alone can induce normal sp ermatogenesis. However, for the induction of mating behavior, suppleme ntation with testosterone is necessary. We have here investigated, by in vitro fertilization, whether sperm produced by photoinhibited hamst ers treated with FSH alone can fertilize without testosterone. Photoin hibited hypogonadal male Djungarian hamsters were injected daily with human FSH (10 IU; Fertinorm) for 5-7 weeks. The hormone stimulated reg rowth of the testes. Neither body weight nor the weights of the androg en-dependent organs - epididymides, prostates, accessory glands - show ed significant differences from photoinhibited controls; furthermore F SH treatment did not raise intratesticular or serum testosterone level s. In eleven out of the twelve FSH-treated photoinhibited hamsters, el ongated spermatids were found in the testes; in five out of nine epidi dymides, sperm was found by histological examination. In two out of th e twelve FSH-treated hamsters, the amount of sperm in the caudal part of the epididymis was sufficient for in vitro fertilization with oocyt es collected from superstimulated females. These spermatozoa fertilize d 16-29% of the oocytes. Spermatozoa from photostimulated controls pro duced similar levels of fertilization.