Acute and Chronic Effects of Captopril on Bicyclo-PGEm, the Stable Bicyclic End Product of Prostaglandin E2 in Essential Hypertension

Abstract

Hemodynamic and hormonal actions of acute (50 mg) and chronic (150 mg/day) captopril were tested in 10 patients with essential hypertension. Under short-term conditions blood pressure was reduced, heart rate and plasma adrenaline did not change, plasma angiotensin II and plasma aldosterone decreased. Plasma renin activity, basal plasma noradrenaline and bicyclo-PGEm, a novel stable metabolite of prostaglandin E₂, increased after captopril. With chronic captopril treatment blood pressure was reduced after 4 weeks before readministration of captopril, heart rate did not change, plasma renin activity and bicyclo-PGEm remained elevated for 12 h after the last captopril dose. Angiotensin II remained suppressed, aldosterone and plasma catecholamines did not change between doses. Readministration of captopril led to a further reduction in blood pressure. Angiotensin II and aldosterone were further suppressed, bicyclo-PGEm levels increased from a higher baseline. Heart rate and plasma catecholamines did not change. Taken together, the results suggest that prostaglandin E₂ is involved in the acute and chronic hypotensive response of captopril in patients with essential hypertension.