Differential radiosensitivity of germ-cells of the male mouse

Male mice of the BALB/C⁺ strain were irradiated on the testis with 300 r of X-rays and during 8 weeks mated with virgin females. The females were exchanged for virgin females twice a week. Seventeen days after they were put into the cages with the males, the females were dissected and the number of corpora lutea and the living and dead embryos recorded. The fertiIity appeared to decrease with the time after irradiation and was the lowest after 6 weeks. The preimplantation loss was at a maximum of 4, 5 and 6 weeks after treatment. It is conceivable that preimpIantation loss is due to a loss of fertilizing capacity of the sperm irradiated at the spermatocyte stage. The postimplantation loss showed that the hypersensitivity period affects the spermatids at all stages.