Characterization of a peptide endothelium-derived constricting factor EDCF.
Endothelium regulates vascular tone by the release of dilator and constrictor mediators. Among the latter, besides endothelin, an 'endothelium derived constricting factor' EDCF sensitive to cyclooxygenase-inhibitors has been described. The aim of this study was to clarify the nature of this EDCF. Eluate from porcine aortic segments or supernatants (crude extracts) of porcine aortic segments were each tested for vascular effects in a bioassay system consisting of two endothelium-denuded acceptor vessels (rabbit abdominal aorta) before or after treatment with trypsin. The donor vessels were incubated with physiological saline solution with or without treatment with cycloheximide, quinacrine or indomethacine. Ultrafiltrates and fractions of a gelfiltration of the supernatants were also tested and compared with SDS-PAGE of these extracts. Finally, porcine aortic endothelial cells (PAEC) were cultured and the supernatant compared with that of the native aortae. A vasoconstrictive factor was released from the luminal surface of the porcine aortic segments, which if infused into the rabbit aortas induced two succeeding vasoconstrictions of 15-20 min duration each (the first 20 min after the first of extract-infusion, the second after 50 min) reaching 7% amplitude of a 0.2 mumol 1(-1) norepinephrine-induced constriction. These constrictions were enhanced if the crude extract of the porcine aortae was concentrated. This constricting factor was a protein with an approximative molecular weight of 9.000 Da. The release of this factor was insensitive to cycloheximide pretreatment indicating no de novo synthesis. However, the release of the factor could be markedly (50%) depressed by pretreatment with either quinacrine or indomethacine. The factor was not released from cultured PAEC. From these results, we conclude, that besides endothelin, endothelium luminally can release another endothelium-derived constricting factor named EDCF, a peptide with a molecular weight of 9.000 Da, which is not identical to endothelium and can induce long lasting vasoconstrictions. The release or synthesis of that EDCF seems to depend on cyclooxygenase and phospholipase A2 activity. We, thus, propose the name PLA2-sensitive EDCF for that factor.
Dhein
S
S
Institut für Pharmakologie, Universität zu Köln, Germany.
Hartmann
E
E
Salameh
A
A
Klaus
W
W
D000704:Analysis of Variance; D000818:Animals; D001012:Aorta, Abdominal / Q000378:metabolism; D001013:Aorta, Thoracic / Q000378:metabolism; D002478:Cells, Cultured / Q000378:metabolism; D016232:Endothelins / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism*; D008297:Male; D011817:Rabbits; D013552:Swine; D014662:Vasoconstrictor Agents / Q000378:metabolism
D016232:Endothelins; D014662:Vasoconstrictor Agents