GONADOTROPHIC RESPONSE OF THE OVARIES OF THE ALBINO MOUSE FOLLOWING CHRONIC LOW-INTENSITY GAMMA IRRADIATION

Abstract

SUMMARY Immature female albino mice were exposed to 60Co irradiation at rates of 20 r. and 40 r./day to total doses of 250,500,750 and 1000 r. Those irradiated at 40 r./day during the 1st week of life showed only one-third of the normal increase in uterine and ovarian weight after injection of human chorionic gonadotrophin (HCG) when 25 days old. No further decline in response was seen when the total dose was increased from 250 to 1000 r. Irradiation at 20 r./day to total doses of 500 r. produced little change in normal HCG response. In contrast, sexually mature adults exposed at 40 r./day to total doses of 1000 r. showed little response to HCG. Histological examination of ovaries from immature mice exposed to doses of 250, 500 and 1000 r. at 40 r./day revealed a depopulation of primary oocytes and early maturing follicles as well as a notable decrease in ovarian size.