Abnormal diurnal variation of plasma cortisol in patients with renovascular hypertension.

ABSTRACT Variation of diurnal plasma cortisol concentration has been studied in a group of patients with hypertension resulting from renal artery obstruction, a process known to cause release of increased amounts of renin. Twelve of 16 patients had grossly abnormal diurnal variation of plasma cortisol concentration with high late evening concentration and low-normal to normal morning concentration. Excretion of 17-hydroxycorticoids was elevated in only 3 of 12 patients, while aldosterone excretion was normal in all of 13 patients studied. The data suggest that angiotensin at low concentrations affects smooth muscle in peripheral arterioles and has no effect on the adrenal cortex. The effect on the adrenal in man, as in experimental animals, is apparently diffuse rather than specific.