Hemmung der Hormonfreisetzung aus dem Nebennierenmark durch BAY a 6781, eine antihypertensiv wirksame Substanz

Summary

In vitro and in vivo experiments have been performed in order to study the effect of BAY a 6781 on the release of the adrenal medullary hormones.

• 1. In the isolated perfused preparation of the bovine adrenal gland, injections of BAY a 6781 up to 100 Μg did not change the rate of spontaneous catecholamine release.

• 2. In contrast, the increased hormone release induced by injections of carbachol andΒ-phenylethylamine was inhibited during an infusion of 1 Μg/ml BAY a 6781 by 68 and 48%, respectively.

• 3. In experiments on anaesthetized cats the hormone release from the adrenal medulla into the blood of the adrenolumbar vein was determined fluorimetrically. Intraaortal injections of BAY a 6781 in doses of 1.6, 5 and 15 Μg/kg reduced the catecholamine release evoked by splanchnic nerve stimulation by 35, 46 and 47%, respectively.

• 4. The hormonal secretion of the adrenal medulla under resting conditions was not altered by the above-mentioned doses of BAY a 6781; moreover the ratio of adrenaline to noradrenaline in the adrenal venous blood remained constant even after splanchnic stimulation.