[Studies on the influence of acute maternal stress on the fetal endocrine system in late gestation of rats].

Prenatal stress affects fetal androgen milieu in the critical period of androgen-dependent brain differentiation, and induces permanent defects in reproductive functions of the offspring. We investigated the response of the fetal hypothalamo-pituitary-adrenal axis and the function of the placenta during an acute maternal stress, in order to clarify the mechanism of central endocrine regulation in the fetus with an inappropriate androgen level under stress. Pregnant rats at day 20-21 of gestation were subjected to forced immobilization stress. The plasma concentration of corticosterone (B) and ACTH, and tissue content of CRF and beta-EP like immunoreactivities (CRF-LI, beta-EP-LI) in the maternal and fetal hypothalamus and the placenta were measured by RIA. 3H-B was administered intravenously to pregnant rats and radioactivity was measured in blood and the hypothalamus. 1. In mothers, plasma B and ACTH increased at 20 and 60 minutes of stress. Hypothalamic CRF-LI decreased and beta-EP tended to decrease during stress. 2. In fetuses, plasma B and ACTH increased significantly during maternal stress. 3. Fetal hypothalamic CRF-LI and beta-EP-LI decreased significantly in males and females under maternal stress. 4. beta-EP-LI in the placenta decreased significantly after 120 minutes of stress, and beta-EP-LI was localized in trophoblast. No CRF-stained cell was detected in the placenta. 5. 3H-B given to mothers passed through the placenta, and the maximum radioactivity in fetal blood and the hypothalamus was found at 20 minutes after the injection.(ABSTRACT TRUNCATED AT 250 WORDS)