Radioresponse of the Pre-puberal Porcine Ovary

Abstract

To determine the effects of gamma-radiation on the pre-puberal procine ovary, either whole-body or localized exposures were used. With whole-body irradiation, 115 gilts of mixed breeding were apportioned to age-groups of 20, 40, 80, and 100 days and dosage groups of either 200 or 350 R of 60Co gamma-radiation (1.5 R/min.). Ovaries of 19 miniature pigs of the Pitman-Moore strain, aged 30 to 50 days, were exteriorized and exposed locally to 137Cs gamma-radiation in doses of 200 to 1000 R (27 R/min.). At 3Q days after irradiation, a super-follicular effect was induced by 200 R in ovaries of animals aged either 40 or 80 days at irradiation; but follicular growth was universally suppressed by 350 R. Numbers of primordial follicles were unaffected by 200 R, but a reduction of 26% unrelated to age was induced by 350 R. In general, radiation reduced follicular quality, and in ovaries excised at 9 to 11 months after irradiation this continued as one of the principal evidences of a radiation effect. At slaughter, 11 of 32 gilts irradiated with 200 R, 16 of 41 gilts irradiated with 350 R, and 1 of 12 control gilts were not pregnant. Ovaries of the infertile animals were characterized by cystic corpora lutea. Data resulting from localized exposures established 500 R as the approximate LD50 for the primordial follicle of the pre-puberal pig.