Differences in renal and submaxillary renin release after stimulation with isoprenaline and noradrenaline.

It is confirmed that while noradrenaline stimulates release of submaxillary as well as renal renin, isoprenaline only stimulates renal renin release. The effects of these two adrenergic agonists differ in several other ways. The kidneys respond to isoprenaline with a dose dependant renin release. As a contrast the submaxillary glands respond to noradrenaline by no or by non-dose-dependant release. After single doses of the agonists the isoprenaline induced renin release is of short duration, contrasting with a prolonged renin release after injection of noradrenaline. The kidneys are able to respond to repeated doses of both agonists, while the submaxillary glands most often only respond to the first dose. While the effect of noradrenaline is blocked by pretreatment with phenoxybenzamine, this blocker is without effect when given after noradrenaline. The two agonists do not provoke any increase in plasma renin in mice which have been both sialoadenectomized and nephrectomized.