抄録
In this study we investigated the response of the rat fetal hypothalamo-pituitary-adrenal (HPA) axis to an acute maternal stress in late gestation.
On day 20 of gestation, pregnant rats were exposed to forced immobilization stress for up to 60min. In mothers, a significant increase in plasma ACTH and corticosterone (B) was observed at 20 and 60min. The ACTH content in the maternal pituitary decreased significantly at 60min. Fetal blood pH was decreased by the maternal stress, showing a hypoxic condition of the fetus. Fetal plasma ACTH increased transiently at 20min. Fetal plasma B increased at 20 and 60min. ACTH in the fetal pituitary and the placenta did not show marked changes due to the maternal stress.
Pregnant rats on day 18-21 of gestation were subjected to a 20min maternal stress. In the basal condition without stress, fetal plasma ACTH and B showed parallel ontogenic patterns, having a peak value on day 19 of gestation. Fetal plasma ACTH as well as plasma B were increased significantly by the maternal stress at all points evaluated. These results indicate that fetal hypoxia is important in stress transmission to the fetal HPA axis in this type of maternal stress, and the fetal HPA axis responds to the stress as early as day 18 of gestation.
