title: Hypoxaemia and release of endothelin-1.
abstract: BACKGROUND
  Secretion of the vasoconstrictor peptide endothelin-1 from vascular endothelium is increased by various stimuli. Whether hypoxaemia affects plasma levels of endothelin-1 in humans is unknown, but this may be important in the haemodynamic response to hypoxaemia. The plasma endothelin-1 concentrations in hypoxaemic humans has therefore been measured.
  
  
  METHODS
  Plasma levels of endothelin-1 were measured by specific radioimmunoassay in 10 control subjects at rest and following 30 minutes of acute hypoxaemia (SaO2 75-80%) induced by breathing a nitrogen/oxygen mixture, and in 10 patients with hypoxaemic cor pulmonale.
  
  
  RESULTS
  The plasma endothelin-1 concentration in control subjects was increased from a mean (SE) of 0.90 (0.11) pmol/l at baseline to 2.34 (0.34) pmol/l during hypoxaemia. In patients with cor pulmonale the plasma endothelin-1 concentration was 2.96 (0.34) pmol/l, raised in comparison with control subjects at rest but similar to levels in controls during hypoxaemia.
  
  
  CONCLUSIONS
  Plasma levels of endothelin-1 were increased by hypoxaemia in humans. The raised levels observed in patients with cor pulmonale may largely be attributable to the effects of hypoxaemia, although the pathophysiological significance of these observations remains to be established.
authors.affiliation: Department of Clinical Pharmacology, Ninewells Hospital and Medical School, Dundee, UK.
authors.forename: R I
authors.initials: RI
authors.lastname: Cargill
authors.forename: D G
authors.initials: DG
authors.lastname: Kiely
authors.forename: R A
authors.initials: RA
authors.lastname: Clark
authors.forename: B J
authors.initials: BJ
authors.lastname: Lipworth
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D016232:Endothelins / Q000097:blood* / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000097:blood* / Q000503:physiopathology; D008297:Male; D011660:Pulmonary Heart Disease / Q000097:blood / Q000503:physiopathology; D011863:Radioimmunoassay
chemical_list: D016232:Endothelins