Hypertension in primary glomerulonephritis without renal insufficiency.

Hypertension is frequently present in glomerulonephritis without renal insufficiency but its pathogenesis is poorly understood. Eighty-five patients with glomerulonephritis and normal renal function, including 55 hypertensive patients, and 24 normal subjects were studied to obtain data on the mechanisms responsible for hypertension. Plasma renin activity (PRA), plasma noradrenaline, total exchangeable sodium, and urinary prostaglandin E (PGE) were determined. Moreover, the autonomic nervous system was explored with the following tests: tilt test, diving reflex, lying down, and deep-breathing tests. In 15 of the 30 normotensive patients with glomerulonephritis, PRA was measured after the administration of propranolol and then indomethacin. No significant differences were found in the mean values of PRA, plasma noradrenaline, total exchangeable sodium, urinary PGE, and autonomic nervous system behaviour between glomerulonephritis patients with and without hypertension or between hypertensive glomerulonephritis patients and control subjects. In many of the normotensive glomerulonephritis patients we found an elevated PRA that was normalised by propranolol but not by indomethacin. In summary, hypertension in glomerulonephritis is not associated with abnormalities in the sodium balance, with renin-angiotensin or with autonomic nervous system abnormalities. A renin hypersecretion seems to be present only in some normotensive patients with glomerulonephritis.