Polydipsia induced by isoprenaline and by lithium: Relation to kidneys and renin

Water intake in rats was increased by the administration of either isoprenaline or LiCl. The polydipsia induced by both drugs was completely abolished following bilateral nephrectomy. Bilateral ligature of the ureters did not eliminate the isoprenaline-induced drinking but decreased considerably the effect of lithium on water intake. Water intake after bilateral ligature of the ureters was significantly larger than that following bilateral nephrectomy. Isoprenaline and LiCl significantly increased plasma renin activity. Propranolol abolished both the rise of plasma renin activity and the polydipsia caused by isoprenaline. Renin, injected into rats, increased significantly their water intake. It is suggested that the polydipsia caused by isoprenaline and by lithium chloride is mediated through the release of renin.