Effects of ACTH and the Adrenals on Serum and Antral Gastrin Levels in the Rat

Abstract

The effect of adrenal hormones and ACTH on serum and antral gastrin levels was examined in intact, adrenalectomized, hypophysectomized, and hypophysectomized-adrenalectomized rats. Hydrocortisone significantly increased antral gastrin within 90 min after injection of 16 or 32 mg/kg in intact rats. It failed to change serum levels. Adrenalectomy did not significantly change either serum or antral gastrin. Hypophysectomy decreased both antral and serum gastrin concentrations to a small fraction of normal. Corticosterone completely prevented the drop in tissue levels and significantly increased serum levels. These data indicate that adrenal hormones can increase tissue levels of gastrin but that this effect does not normally occur under physiological conditions with adequate supplies of growth hormone. ACTH increased serum gastrin levels in both hypophysectomized and hypophysectomized-adrenalectomized rats. Therefore, ACTH acts directly to release gastrin. However, this effect was noted only in the absence of the pituitary.