Functional role, cellular source, and tissue distribution of rat elastase-2, an angiotensin II-forming enzyme.
We recently described a chymostatin-sensitive elastase-2 as the major angiotensin (ANG) II-forming enzyme in the perfusate of the rat mesenteric arterial bed (MAB) with the same cDNA sequence as rat pancreatic elastase-2. The role of this enzyme in generating ANG II was examined in the rat isolated and perfused MAB. The vasoconstrictor effect elicited by ANG I and the renin substrate tetradecapeptide was only partially inhibited by captopril but abolished by the combination of captopril and chymostatin or N-acetyl-Ala-Ala-Pro-Leu-chloromethylketone (Ac-AAPL-CK; inhibitor originally developed for human elastase-2). The effect induced by [Pro11,d-Ala12]-ANG I, an ANG I-converting enzyme (ACE)-resistant biologically inactive precursor of ANG II, was blocked by chymostatin or Ac-AAPL-CK. It was also demonstrated that cultured rat mesenteric endothelial cells synthesize elastase-2 and that mRNA for this enzyme can be detected in different rat tissues such as the pancreas, MAB, lung, heart, kidney, liver, and spleen. In conclusion, the demonstration of a functional alternative pathway to ACE for ANG II generation in the rat MAB and the fact that cultured MAB endothelial cells are capable of producing and secreting elastase-2 represent strong evidence of a physiological role for this enzyme in the rat vasculature.
Santos
Carlos F
CF
Department of Pharmacology, University of São Paulo School of Medicine, Ribeirão Preto 14049-900, Brazil.
Caprio
Marcos Antonio V
MA
Oliveira
Eduardo B
EB
Salgado
Maria Cristina O
MC
Schippers
Daniela N
DN
Munzenmaier
Diane H
DH
Greene
Andrew S
AS
D000804:Angiotensin II / Q000096:biosynthesis*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D002216:Captopril / Q000494:pharmacology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000201:enzymology*; D009842:Oligopeptides / Q000494:pharmacology; D010477:Perfusion / Q000592:standards; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012697:Serine Endopeptidases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D014781:Viscera / Q000201:enzymology
D000806:Angiotensin-Converting Enzyme Inhibitors; D017077:Culture Media, Conditioned; D009842:Oligopeptides; D012333:RNA, Messenger; D015842:Serine Proteinase Inhibitors; D000804:Angiotensin II; C002101:chymostatin; D002216:Captopril; D012697:Serine Endopeptidases; C117309:pancreatic elastase II