[Correlation between the inhibition of renin-angiotensin system and antihypertensive effect of MK-421 and captopril in 2-kidney, 1-clip renal hypertensive rats after single and repeated oral administration of MK-421 or captopril].
The angiotensin converting enzyme (ACE) activity in tissues and plasma renin activity (PRA) were measured in 2-kidney, 1-clip renal hypertensive rats (2K-RHR) and normotensive rats after a single and 3-weeks oral administrations of ACE inhibitors such as MK-421 and captopril. In the single dose study, MK-421 (1 and 3 mg/kg) and captopril (3 and 10 mg/kg) inhibited the ACE activities in kidney, aorta and plasma in a dose-dependent fashion. The inhibition of ACE activity in kidney or aorta was observed for a longer time than that in plasma. PRA took a time course reversal to that of plasma ACE activity. In the 3-weeks repeated dose study, the ACE activity in kidney and aorta was strongly inhibited after the administration of each ACE inhibitor, while there was no significant change in lung ACE activity at any time point examined. The plasma ACE activity markedly elevated after the administration of each agent. PRA significantly increased after the administration of either agent, while the plasma angiotensin II level was significantly inhibited. These results indicate that the inhibition of the ACE activity in blood vessel or kidney correlate well with the antihypertensive activity in 2K-RHR after a single and repeated administration of both ACE inhibitors, but not well with the inhibition of plasma ACE activity.
D000806:Angiotensin-Converting Enzyme Inhibitors; D000818:Animals; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001011:Aorta / Q000201:enzymology; D002216:Captopril / Q000627:therapeutic use*; D004656:Enalapril / Q000627:therapeutic use*; D006977:Hypertension, Renal / Q000188:drug therapy* / Q000378:metabolism; D007668:Kidney / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System / Q000187:drug effects*
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D004656:Enalapril; D002216:Captopril; D012083:Renin