Fetal x-irradiation and fertility.

Abstract

Summary and Conclusions1. Mice x-irradiated in utero to 300 r accumulated in 6 exposures of 50 r each on 6 consecutive days beginning on the 14th day of gestation, reveal various degrees of sterility at 6 months, the period of peak reproductive activity in the mouse. The 10 pregnant females, producing these litters, were all made sterile by this x-irradiation. 2. Within any single litter, there were variations in response of fetuses indicating, possibly, a slight spread in the developmental stage of the gonad primordia at the instant of x-irradiation. Certainly one can hardly visualize a dosimetry sufficiently different within a fetal litter to account for the variations in response. 3. Testes sterility was correlated with the relative number of seminiferous tubules in which maturation stages occur. In those testes where 40% or more of the tubules contain maturation figures, the male was fertile. The completely sterile testes contained 10% or less of tubules having maturation stages. 4. The precursors of ...