Dexamethasone and Corticosterone Administration to Pregnant Rats: Effects on Pituitary-Adrenocortical Function in the Newborn 1

Summary and conclusions

Deficiency or excess of adrenocorticosteroids in the mother is associated with significant alterations in activity of the fetal pituitary-adrenal system of the rat. Hypophysectomy of the pregnant rat results in increased weight and corticosterone content of the adrenal and depletion of pituitary ACTH in the neonate. Administration of corticosteroids to hypophysectomized pregnant rats produces atrophy of the newborn's adrenal and inhibition of ACTH secretion by the neonatal pituitary. It is postulated that maternal adrenocorticosteroids cross the placenta in the perinatal period to exercise a restraining influence on ACTH secretion by the fetal hypophysis.

The authors thank Mr. Wall of Merck, Sharp and Dohme Research Laboratories, Rahway, New Jersey for generous supplies of dexamethasone-21-phosphate.