Effect of Acute Stress on the Pituitary Gland: Action of Ethionine on Stress-Induced ACTH Release1

Abstract

The effect of subcutaneous administration of ethionine was studied on stress-induced ACTH release in female rats. Ethionine was shown not to affect adrenal ascorbic acid content, pituitary ACTH content, or the adrenal ascorbic acid depleting effect of test doses of ACTH. Ethionine produced a marked suppression of ACTH release following ether-laparotomy stress. The suppression was most marked 1 hr after ethionine injection. The effect of ethionine was antagonized by simultaneous administration of methionine. Ethionine also suppressed stressinduced ACTH release in 1 day and 30 day adrenalectomized rats, but did not affect the resting level of blood ACTH. Ethionine prevented the stress-induced rise in pituitary ACTH content of adrenalectomized rats, but did not affect the resting level of ACTH in these rats. It was concluded that ACTH release after stress involved the new synthesis of ACTH, while the basal or resting secretion of ACTH was a function of the pituitary stores of this hormone.