Renal abnormalities in nonmodulating essential hypertension.

Hypertensives with low renin levels are known to be sensitive to salt intake and diuretics. The subset of hypertensives sensitive to salt and having normal or high renin levels are termed nonmodulators. These are patients with essential hypertension who fail to modulate their renal blood flow and aldosterone responsiveness to angiotensin II when dietary sodium is changed. The result of nonmodulation is a pressor response to a short-term sodium load that results from a failure to excrete the sodium appropriately and that is presumably secondary to the defect in renal blood supply. On a high sodium load only nonmodulators have a decrease in BP in response to short-term treatment with an angiotensin-converting enzyme (ACE) inhibitor, which indicates an abnormality in intrarenal angiotensin II levels or in the renal angiotensin II receptor.