Fluctuations in the plasma angiotensin I converting enzyme activity during long-term treatment with captopril.
Eight hypertensive patients on chronic captopril treatment were studied: blood pressure, plasma converting enzyme activity (pCEA) and various components of plasma renin-angiotensin-aldosterone system were measured repeatedly, immediately before and up to 7 hours after the usual morning dose of captopril in 5 patients, or a matching placebo in 3 patients. In the patients, receiving a placebo no significant changes were observed over a 7 hour period in pCEA, plasma rénin activity (PRA), plasma angiotensin II (ANG II) plasma aldosterone (PAC) and blood pressure. In patients receive captopril (200 mg) pCEA rapidly decreased, reaching after 2 hours a minimum, corresponding to nearly 20 per cent of its reference value. Thereafter pCEA increased and after 7 hours remained only slightly depressed. Within the first hour after captopril intake a small but significant decrease of ANG II and PAC was observed, while PRA and blood pressure remained unchanged throughout the study period. A continuous low pCEA level is therefore not necessary to achieve a sustained blood pressure lowering effect during chronic captopril treatment.
D000328:Adult; D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects*; D002216:Captopril / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D007703:Peptidyl-Dipeptidase A / Q000097:blood*; D011392:Proline / Q000031:analogs & derivatives*; D012083:Renin / Q000097:blood
D000804:Angiotensin II; D000450:Aldosterone; D011392:Proline; D002216:Captopril; D007703:Peptidyl-Dipeptidase A; D012083:Renin