Effect of glycyrrhizin on the suppressive action of cortisone on the pituitary adrenal axis

Abstract

The effects of glycyrrhizin on the pituithry adrenal axis were studied. Isolated rat anterior pituitary glands were incubated with 14C-phenylalanine and biosynthetic activity of corticotropin in the pituitary was estimated. The rate of incorporation of radioactivity from 14C-phenylalanine into corticotropin fraction in the rat anterior pituitary was increased specifically by prior adrenalectomy. Cortisone treatment suppressed the increased 14C-incorporation into the corticotropin fraction induced by prior adrenalectomy. However concomitant injections of glycyrrhizin blocked the inhibitory action of cortisone on 14C-incorporation into the corticotropin fraction. Glycyrrhizin was also found to be antagonistic to the suppressive action of cortisone on compensatory adrenal hypertrophy in rats after unilateral adrenalectomy. Under condition of stress, glycyrrhizin was found to increase the inhibitory action of cortisone on adrenal ascorbic acid depletion. The possibility of distinguishing the secretory mechanism of corticotropin in the basal stage from that in the condition of stress and the mechanism of the inhibition of glycyrrhizin on the action of cortisone are discussed. © 1966, The Japan Endocrine Society. All rights reserved.