Differential uptake of endothelin-1 by the coronary and pulmonary circulations

J Appl Physiol (1985). 1992 Aug;73(2):557-62. doi: 10.1152/jappl.1992.73.2.557.


Substantial removal of the vasoconstrictor peptide endothelin-1 (ET-1) by the pulmonary circulation has been reported to occur in perfused guinea pig and rat lungs. We examined the uptake of ET-1 by coronary and pulmonary circulations of the rabbit by measuring single-pass extraction of ET-1 in the isolated heart and lung. In separate experiments, each organ was perfused at 30 ml/min with Krebs-albumin (3%) solution. A bolus of 125I-ET-1 and [14C]dextran in 0.3 ml Krebs-albumin solution was injected, and extraction of endothelin (EET), relative to that of an intravascular reference indicator, [14C]dextran, was determined by multiple indicator-dilution technique. EET was 5 +/- 2% (SE) in the heart and 49 +/- 4% in the lung. Increasing flow rate in the lung preparation to approximate the mean transit time in the heart preparation did not significantly alter EET. Despite insignificant uptake of ET-1, the coronary circulation extracted an angiotensin-converting enzyme inhibitor (351A) and metabolized a synthetic angiotensin-converting enzyme substrate (benzoyl-phenyl-alanyl-proline), both properties of the normal pulmonary circulation. We therefore conclude that there is no significant ET-1 uptake in the coronary vascular bed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Angiotensin-Converting Enzyme Inhibitors / pharmacology
  • Animals
  • Coronary Circulation / physiology
  • Dextrans
  • Endothelins / metabolism*
  • In Vitro Techniques
  • Iodine Radioisotopes
  • Lung / metabolism*
  • Myocardium / metabolism*
  • Perfusion
  • Pulmonary Circulation / physiology
  • Rabbits


  • Angiotensin-Converting Enzyme Inhibitors
  • Dextrans
  • Endothelins
  • Iodine Radioisotopes