Role of elastase-2 as an angiotensin II-forming enzyme in rat carotid artery.
We have described the biochemical, enzymatic, and structural properties of a chymostatin-sensitive angiotensin (Ang) I-converting elastase-2 found in the rat mesenteric arterial bed perfusate. We determined the mRNA for elastase-2 and its relative role in generating Ang II in the rat isolated aorta and carotid artery rings. In carotid rings, the Ang I-induced vasoconstrictor effect was only partially inhibited by captopril or chymostatin, whereas that of tetradecapeptide renin substrate (TDP) was greatly inhibited by chymostatin but unaffected by captopril; however, Ang I- and TDP-induced effects were abolished by the combination of both inhibitors. Effects of [Pro11-D-Ala12]-Ang I (PDA), an Ang I-converting enzyme (ACE)-resistant biologically inactive precursor of Ang II were blocked by chymostatin or N-acetyl-Ala-Ala-Pro-Leu-chloromethylketone (elastase-2 inhibitor) in carotid artery. PDA failed to induce an effect in aortic rings, and Ang I-induced contractions were completely inhibited by captopril. The mRNA for rat elastase-2 was detected in aorta, carotid, and mesenteric arteries, although its expression was found to be less important in aorta. These findings indicate the presence of a functional alternative pathway to ACE for Ang II generation in rat carotid artery and represent strong evidence of a physiological role for elastase-2; however, its functional contribution to Ang II formation in aorta appears to be negligible.
Becari
Christiane
C
Department of Pharmacology, University of São Paulo, School of Medicine of Ribeirão Preto, Ribeirão Preto, Brazil 14049-900.
Sivieri
Disney O
DO
Santos
Carlos F
CF
Moysés
Milene K
MK
Oliveira
Eduardo B
EB
Salgado
Maria Cristina O
MC
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000803:Angiotensin I / Q000494:pharmacology; D000804:Angiotensin II / Q000378:metabolism* / Q000494:pharmacology; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000808:Angiotensinogen / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D002216:Captopril / Q000494:pharmacology; D017536:Carotid Artery, Common / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects
D000590:Amino Acid Chloromethyl Ketones; D000806:Angiotensin-Converting Enzyme Inhibitors; D009842:Oligopeptides; D012333:RNA, Messenger; D015842:Serine Proteinase Inhibitors; D000808:Angiotensinogen; D000804:Angiotensin II; D000803:Angiotensin I; C002101:chymostatin; D002216:Captopril; D012697:Serine Endopeptidases; C117309:pancreatic elastase II