Oocyte loss in macaques from chronic tritiated water exposure before birth

Because massive oocyte loss had been found in squirrel monkeys following low-level /sup 3/HOH exposure prenatally, two species of macaque, rhesus and bonnet monkeys (Macaca mulatta and M. radiata), were studied to test whether intense germ-cell radiosensitivity exists also in other primates before birth (hence perhaps in man). Adult females received 5 μCi/ml of /sup 3/HOH in drinking water from the time pregnancy was hormonally confirmed until shortly after parturition, giving measured body-water levels of 4 μCi/ml, delivering 0.9 rad/day. From the female offspring, ovaries were removed soon after birth and at 6 months; oocytes were enumerated in serial sections. In the newborns, germ-cell deficiencies (comparisons with controls) were about 20%, much less than seen in squirrel monkeys. By 6 months, however, losses were striking: 60% in rhesus and 95% in bonnet monkeys. Such losses, from less than 1 rad/day and seen varyingly in all three primate species examined, warn of possible high prenatal germ-cell vulnerability in the human female