Effects of Metopirone on Urinary Excretion of Adrenaline, Noradrenaline and Vanylmandelic Acid in Different Physiological Conditions. The Possible Role of Adrenal Cortex in Catecholamine Degradation

Abstract

The experiments show the effect of Metopirone on urinary excretion of free adrenaline, noradrenaline and vanylmandelic acid in rats. The effects of Metopirone on urinary excretion of catecholamines are more severe in normal rats than in adrenalectomized rats. The adrenal cortex seems to be associated with the processes of catecholamine degradation. The extent to which the adrenal cortex influences catecholamine degradation is determined by measuring vanylmandelic acid (VMA) in hypophysectomized rats. Compensation of the adrenal cortex with ACTH in hypophysectomized rats brings the VMA excretion to control level. Metopirone reduces noradrenaline and VMA excretion while it elevates adrenaline regardless of the adrenal gland. The results suggest that adrenal cortex serves as a rate limiting factor for catecholamine degradation in normal rats.

Key words

Adrenaline - Noradrenaline - Vanylmandelic Acid - Metopirone - Catecholamine Degradation