Document Detail


Phosphoramidon blocks the pressor activity of big endothelin[1-39] and lowers blood pressure in spontaneously hypertensive rats.
MedLine Citation:
PMID:  1725358     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In porcine aortic endothelial cells, the 21-amino acid peptide endothelin-1 (ET-1) is formed from a 39-amino acid intermediate big endothelin (big ET) by a putative endothelin-converting enzyme (ECE) that cleaves the 39-mer at the Trp21-Val22 bond. Because big ET has less than 1% of the contractile activity of ET-1, inhibition of ECE should effectively block the biological effects of big ET. Big ET injected intravenously into anesthetized rats produces a sustained pressor response that presumably is due to conversion of big ET to ET-1 by ECE. We determined the type of protease activity responsible for this conversion by evaluating the effectiveness of protease inhibitors in blocking the pressor response to big ET in ganglion-blocked anesthetized rats. The serine protease inhibitor leupeptin, the cysteinyl protease inhibitor E-64, and the metalloprotease inhibitors captopril and kelatorphan were ineffective at blocking the pressor response to big ET. However, the metalloprotease inhibitors phosphoramidon and thiorphan both dose-dependently inhibited the pressor response to big ET, although phosphoramidon was substantially more potent than thiorphan. None of the inhibitors blocked the pressor response to ET-1 and none had any effect on blood pressure when administered alone as an i.v. bolus to the ganglion-blocked anesthetized rat. However, phosphoramidon infused intravenously at 20 mg/kg/h for 4 h lowered the mean arterial pressure (MAP) in conscious spontaneously hypertensive rats (SHRs) whereas kelatorphan at the same dose did not. Our results suggest that ECE is a novel metalloprotease and that ECE inhibitors could have therapeutic potential for the treatment of hypertension.
Authors:
E G McMahon; M A Palomo; W M Moore
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of cardiovascular pharmacology     Volume:  17 Suppl 7     ISSN:  0160-2446     ISO Abbreviation:  J. Cardiovasc. Pharmacol.     Publication Date:  1991  
Date Detail:
Created Date:  1992-05-12     Completed Date:  1992-05-12     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  7902492     Medline TA:  J Cardiovasc Pharmacol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  S29-33     Citation Subset:  IM    
Affiliation:
Searle Research & Development, G. D. Searle & Co., St. Louis, MO 63167.
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MeSH Terms
Descriptor/Qualifier:
Animals
Aspartic Acid Endopeptidases / antagonists & inhibitors
Blood Pressure / drug effects*
Dose-Response Relationship, Drug
Endothelin-1
Endothelins / antagonists & inhibitors*
Glycopeptides / pharmacology*
Hypertension / drug therapy*,  physiopathology
Male
Metalloendopeptidases
Protease Inhibitors / pharmacology
Protein Precursors / antagonists & inhibitors*
Rats
Rats, Inbred SHR
Rats, Inbred Strains
Rats, Inbred WKY
Chemical
Reg. No./Substance:
0/Endothelin-1; 0/Endothelins; 0/Glycopeptides; 0/Protease Inhibitors; 0/Protein Precursors; 36357-77-4/phosphoramidon; EC 3.4.23.-/Aspartic Acid Endopeptidases; EC 3.4.24.-/Metalloendopeptidases; EC 3.4.24.71/endothelin-converting enzyme

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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