Abstract
Hyotensive mechanism of Angiotensin I Converting Enzyme Inhibitor (SQ 14225) was investigated in 10 patients with essential hypertension (EH) and in 4 patients with renovascular hypertension (RVH). After the administration of SQ 14225 (50mg) in two groups, both systolic and diastolic blood presetsure decreased significantly, and the Plasma Aldosterone Concentration (PAC) also showed significant decrease Negative correlation was observed between the pre-administration Plasma Renin Activity (PRA) levels and the degree of hypotensive effect. The decrease in total peripheral resistance (TPR) was observed in seven out of 11 cases in which their blood pressure were lowered. The chronic administration of SQ 14225, 75mg/day, for seven days showed significant hypotensive effect, and negative correlation was observed between the pre-administration PRA and the degree of hypotensive effect. Negative correlation was observed between the increase of serum K* and the degree of the hypotensive effect, and between the urinary Na excretion and the degree of the hypotensive effect in normal renin group of EH and RVH group in which gignif icant hypotensive effect was observed. In the study of ACTH infusion test, the increase in the PAC levels were suppressed after the study of ACTH infusion test, the increase in the PAC levels were suppressed after the administration of SQ 14225. The present study suggest that the main mechanism of SQ 14225 were due to the decrease in endogenous Angiotensin II in the acute phase, and due to the decrease of PAC as well as endogenous Angiotensin II in the chronic phase.
