EFFECTS OF SPACE-FLIGHT ON OVARIAN-HYPOPHYSEAL FUNCTION IN POSTPARTUMRATS

The effect of space flight in a National Aeronautics and Space Adminis tration (NASA) shuttle was studied in pregnant rats. Rats were launche d on day 9 of gestation and recovered on day 20 of gestation. On day 2 0 of gestation, rats were unilaterally hysterectomized and subsequentl y allowed to go to term and deliver vaginally. There was no effect of space flight on pituitary and ovary mass postpartum. In addition, spac e flight did not alter healthy and atretic ovarian antral follicle pop ulations, fetal wastage in utero, plasma concentrations of progesteron e and luteinizing hormone (LH) or pituitary content of follicle stimul ating hormone (FSH). Space flight significantly increased plasma conce ntrations of FSH and decreased pituitary content of LH at the postpart um sampling time. Collectively, these data show that space flight, ini tiated during the postimplantation period of pregnancy, and concluded before parturition, is compatible with maintenance of pregnancy and ha s minimal effects on postpartum hypophyseal parameters; however, none of the ovarian parameters examined was altered by space flight.