Abstract
The catecholamine contents in the adrenal gland and adrenal venous blood of rats were measured in order to investigate the effect of vasopressin on the release of catecholamine from the adrenal medulla.
1) Single or repeated intraperitoneal injections of vasopressin caused no significant change in the catecholamine content in the adrenal glands.
2) During the vasopressin infusion, the amout of adrenaline released into the adrenal venous blood increased in 5 out of 11 rats used, while little change was recognized in the other 6 rats. No appreciable change in noradrenaline release was observed by the infusion of vasopressin.
3) The effect of acetylcholine to stimulate the release of adrenaline from the adrenal medulla was exaggerated by the simultaneous infusion of vasopressin, whereas the release of noradrenaline due to acetylcholine remained unchanged.
The author inferred from the present results that there may be some possibility for vasopressin to increase the release of adrenaline from the adrenal medulla, though it failed to exert any significant influence on the catecholamine content of adrenal glands. Further, vasopressin might enhance the sensitivity of the adrenal medulla to acetylcholine.
