Effects of ACTH, dexamethasone, adrenalectomy and stress on cAMP content of adenohypophysis and adrenals in rats.

The effects of adrenalectomy, ether-laparotomy stress and in vivo administration of either ACTH or dexamethasone on the cAMP levels in the anterior pituitary and the adrenal glands were investigated in male rats. After adrenalectomy or ether-laparotomy stress, an increase of the pituitary cAMP levels was observed. A prior administration of dexamethasone failed to inhibit the increase of the pituitary cAMP levels. Acute administration of dexamethasone increased the cAMP levels in the pituitary. Chronic administration of dexamethasone decreased the cAMP levels in the pituitary, but ACTH did not. These data suggest that cAMP might be involved in the mediation of the hypothalamo-pituitary-adrenal axis.