Influence of converting-enzyme inhibition on rat des-angiotensin I-angiotensinogen.
The effects of high plasma renin levels on plasma levels of both total immunoreactive angiotensinogen (direct radioimmunoassay) and intact angiotensinogen measured by angiotensin I released by renin (indirect assay) were studied in sodium-depleted rats both with and without captopril treatment and in adrenalectomized rats. The direct assay measures both intact angiotensinogen and des-angiotensin I-angiotensinogen, its residue cleaved by renin. The indirect assay measures only intact angiotensinogen. Neither sodium depletion, captopril treatment, nor adrenalectomy modified the circulating levels of total angiotensinogen. However these treatments produced a decrease in intact angiotensinogen that was in proportion to the elevation of renin levels. The difference between the two assays for angiotensin represents the level of des-angiotensin I-angiotensinogen and correlated satisfactorily with the plasma levels of renin. Identical correlations were observed in adrenalectomized rats and captopril-treated rats. We conclude that des-angiotensin I-angiotensinogen levels are an index of activation of the renin-angiotensin system dependent on the circulating level of renin.
D000311:Adrenal Glands / Q000502:physiology; D000315:Adrenalectomy; D000803:Angiotensin I / Q000031:analogs & derivatives / Q000378:metabolism*; D000806:Angiotensin-Converting Enzyme Inhibitors; D000808:Angiotensinogen / Q000378:metabolism*; D000809:Angiotensins / Q000378:metabolism*; D000818:Animals; D002216:Captopril / Q000494:pharmacology; D004039:Diet, Sodium-Restricted; D008297:Male; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System; D012964:Sodium / Q000502:physiology
D000806:Angiotensin-Converting Enzyme Inhibitors; D000809:Angiotensins; D000808:Angiotensinogen; C011437:angiotensin I, des-Asp(1)-; D000803:Angiotensin I; D002216:Captopril; D012964:Sodium; D012083:Renin