Natriuretic hormones in low renin hypertension.

The possible roles of a humoral sodium pump inhibitor and atrial natriuretic peptide in low renin hypertension are considered, relying heavily on data from a classical animal model of low renin hypertension, the reduced renal mass-saline model in the rat, and on data uncovered by a new literature survey of the two agents in various normotensive and hypertensive states. Based on these data, particularly those indicating both agents are released by volume expansion, our current view is that low renin hypertension is in part generated by the sodium pump inhibitor and is in part moderated by atrial natriuretic peptide. We suggest that the atrial natriuretic peptide compensates for increased volume due to reduced renal function and/or increased salt intake and that in low renin hypertension the compensation is not sufficient to return volume and pressure to normal. In this view, the sodium pump inhibitor is prohypertensive, via actions on blood vessels and heart, and atrial natriuretic peptide is antihypertensive, via actions on kidney and the cardiovascular system.