Document Detail


The impact of the endothelin type A receptor on regional endothelin-1 turnover, in particular renal endothelin-1 release, in humans.
MedLine Citation:
PMID:  20150570     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The endothelin type A (ETA) receptor was studied in six healthy subjects on two occasions with or without an ETA receptor (BQ-123) blockade. At 40 min of either BQ-123 or NaCl infusion, a concomitant infusion of the endothelin-1 (ET-1) precursor, big ET-1, was initiated to augment ET-1 formation. Blood samples were taken from catheters in a peripheral artery, the renal and femoral veins, and the pulmonary artery. Forty minutes of infusion with BQ-123 alone increased heart rate (P<0.001) and cardiac output (CO; P<0.01) and depressed mean arterial blood pressure (P<0.001) and systemic vascular resistance (SVR; P<0.01). During infusion of big ET-1 alone, CO, stroke volume, and renal blood flow decreased (P<0.01), whereas SVR and pulmonary and renal vascular resistance increased (P<0.05). These responses to big ET-1 were abolished or diminished by BQ-123. Renal ET-1 release was threefold higher when big ET-1 infusion was preceded by BQ-123 infusion (P<0.001). Arterial ET-1 concentrations rose to similar levels after big ET-1 infusion (P<0.01) in both trials because of elevated concomitant pulmonary uptake (P<0.05) after ETA blockade. Although there was no net ET-1 leg exchange, leg ET-1 turnover was higher after big ET-1 was preceded by BQ-123. Gene expression of endothelin-converting enzyme 1 and ET-1 in skeletal muscle remained unaltered on both occasions. Our data demonstrate that the level of circulating ET-1 is regulated by ETA receptor-mediated negative feedback. This mechanism seems to be coupled to increased conversion of big ET-1 and is most potent in the kidneys. This emphasizes the important physiological role of ETA receptors in the kidneys, and the lung seems to be mainly a clearing organ for ET-1.
Authors:
Eric Rullman; Thomas Gustafsson; Gunvor Ahlborg
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-02-11
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  108     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-06-03     Completed Date:  2010-10-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1625-30     Citation Subset:  IM    
Affiliation:
Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska University Hospital, Huddinge 141 86 Stockholm, Sweden.
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MeSH Terms
Descriptor/Qualifier:
Adult
Endothelin-1 / metabolism*
Humans
Kidney / metabolism*
Male
Metabolic Clearance Rate
Receptor, Endothelin A / metabolism*
Vasomotor System / physiology*
Chemical
Reg. No./Substance:
0/Endothelin-1; 0/Receptor, Endothelin A

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