NONMODULATING TRAIT MAY PRECEDE THE DEVELOPMENT OF HYPERTENSION

The nonmodulating trait thought to explain development of hypertension in 25 to 35% of patients, is characterized by abnormal angiotensin II (AII)-mediated control of aldosterone release and renal blood flow (R BF). Some data support the possibility that nonmodulation is an inheri ted trait, but others argue that it is an acquired epiphenomenon of th e hypertensive state. We report the first case of a normotensive patie nt with nonmodulation who subsequently developed frank hypertension. P atient RR was studied on six occasions over a 5-year period, two while normotensive, four while hypertensive. This patient consistently demo nstrated an abnormally low plasma aldosterone response to AII (3 ng/kg /min) on a low salt (10 mEq sodium) diet while both normotensive and h ypertensive. A consistently abnormally depressed RBF response to AII o n a high salt (150 to 200 mEq sodium) diet as well as a depressed RBF increment when the diet was changed from low salt to high salt were al so noted. Thus, RR demonstrated nonmodulation by multiple criteria whi le both normotensive and hypertensive. We conclude that the nonmodulat ing trait may be a heritable defect that leads to the development of h ypertension and is not an epiphenomenon.