INCREASED SODIUM APPETITE IN ADRENALECTOMIZED OR HYPOPHYSECTOMIZED RATS AFTERINTRACRANIAL INJECTIONS OF RENIN OR ANGIOTENSIN II

Abstract

Rats given free access to food, water and 2·7% NaCl and injected with either renin or angiotensin II into the preoptic area showed an immediate increase in water intake followed by an increase in intake of 2·7% NaCl. The rats continued to drink the hypertonic NaCl solution throughout the test session of 18 h. Intracranial injections of the dipsogen, carbachol, caused thirst but no sodium appetite. Bilateral adrenalectomy had no effect on either the initial water intake or the delayed intake of NaCl that was induced by intracranial injections of renin or angiotensin II. However, the increased water intake during the 18 h after the administration of renin was reduced to normal levels in adrenalectomized rats. Similar results were obtained with hypophysectomized rats. These results demonstrated that the delayed sodium appetite induced by renin or angiotensin II is not secondary to the stimulation of release of hormones from the pituitary gland or adrenal cortex.