Effects of diltiazem hydrochloride on pressor and steroidogenic actions of angiotensins and norepinephrine in man.

Abstract

The effect of diltiazem hydrochloride (DTZ), a Ca antagonist, on pressor and steroidogenic action of angiotensin (A) II, AIII and norepinephrine (NE) was studied in 5 normal men. AII, AIII and NE were infused i.v. for 50 min for 0900 h at a rate of 20 ng/kg per min, 100 ng/kg per min and 200 ng/kg per min, respectively. DTZ was infused i.v. alone or in combination with each of these pressor substances at a rate of 1 mg/min from 0910 h to 0930 h. DTZ alone did not cause significant changes in blood pressure (BP) and plasma aldosterone concentration (PI Aldo). DTZ combined with AII, AIII or NE significantly inhibited the rise in BP induced by these pressor substances. DTZ also inhibited the NE-induced increase in P1 Aldo, whereas it did not alter AII- or AIII-induced increase in P1 Aldo. In normal men pressor actions of AII, AIII and NE are Ca-dependent and Ca ions are also involved in NE-induced increase in P1 Aldo.