[Studies on antifertility effect of testosterone undecanoate in combination with danazol in male rats].

Male rats were injected i.m. with 12 mg/kg testosterone undecanoate (TU) twice in the first and once in each of the succeeding 2 months in combination with oral danazol (DZ) of 30 mg/kg/day. Antifertility effects were observed with morphological and functional techniques for half a year. Results showed: reduction of testis weight and seminiferous tubule diameter; decrease of sperm viability and motility in canada epididymidis; and lowering of testosterone levels in testis and phospholipid and protein contents in epididymis. 75 days after treatment spermatogenesis was arrested mainly in the secondary spermatocyte stage with a decrease in sperm count to 0 in the cauda epididymidis. Mating test showed 0% fertility. Testicular testosterone and epididymis phospholipid and protein contents were found to have dropped further. However, all of the above-mentioned changes recovered completely 100 days after cessation of treatment. The authors suggest that TU plus DZ in a suitable dose suppresses spermatogenesis, retards maturation and shortens the survival time of sperm in the epididymis by reducing testosterone levels in the testis.