Effects of chronic gamma-irradiation on the gonads of adult Ameca splendens (Osteichthyes: Teleostei).

The effects of chronic gamma-irradiation on the gonads of adult Ameca splendens (Osteichthyes: Teleostei) have been investigated at a mean dose rate of 7.3 mGy hour-1 for 5-244 days. Spermatogenesis was disrupted after an accumulated dose of 0.95 Gy (5 days exposure) and after 52 days (9.7 Gy) there was no further production of sperm. The secondary spermatogonia were the most radiosensitive cell type and the primary spermatogonia the most radioresistant, not completely disappearing until day 95 (16 Gy). Males removed from the irradiated aquaria after accumulating doses of 3.9 Gy (21 days) and 7.0 Gy (40 days) showed a high degree of recovery from the radiation damage to spermatogenesis when examined after 125, 174 and 236 days. The developing oocytes were less sensitive to the effects of radiation than the stages of spermatogenesis, not showing any depletion in numbers until day 38 (6.9 Gy).