Peripheral angiotensin II is not the cause of sodium appetite in the rat.

Activation of the renin-angiotensin system has been shown to arouse both water and sodium intake in the rat. The following experiments examine the contributions of the peripheral and central renin-angiotensin systems to the expression of sodium appetite in the adrenal-intact rat. Firstly, we find that, unlike intracerebroventricular angiotensin II, intravenous administration of the hormone at dipsogenic doses does not arouse sodium intake in the sodium replete rat when given alone or in combination with systemic mineralocorticoid pretreatment. Secondly, in the sodium depleted rat, we find that interference with central, but not peripheral, angiotensin II action suppresses sodium appetite. Together, these data confirm recent evidence which demonstrates that it is angiotensin II of cerebral origin, not angiotensin II of renal origin, that is necessary for the expression of sodium appetite.