Effect of adrenal medullectomy on the activity of COMT and MAO in adrenal cortex of control and stressed rats.

The effect of bilateral adrenal medullectomy on the activity of catecholamine degrading enzymes--catechol-o-methyl transferase (COMT) and monoamino oxidase (MAO)--in adrenal cortex and on the level of corticosterone in plasma was studied in the rats subjected either to a single (2.5 h) or repeated (2.5 h daily for 150 days omitting Saturdays and Sundays) immobilization stress. After medullectomy a significant increase of COMT activity was found in adrenal cortex of unstressed controls, while the activity of MAO was significantly decreased. Similar results were observed also in medullectomized animals subjected either to a single or repeated stress. The levels of corticosterone remained unchanged in medullectomized controls, but were significantly decreased in medullectomized and stressed animals. Although the mechanism still remains to be elucidated, these results may be considered as a further contribution to the understanding of the functional interrelations between the adrenal medulla and cortex.