20-hydroxyeicosatetraenoic acid (20-HETE) metabolism in coronary endothelial cells.
We have investigated the role of endothelial cells in the metabolism of 20-hydroxyeicosatetraenoic acid (20-HETE), a vasoactive mediator synthesized from arachidonic acid by cytochrome P450 omega-oxidases. Porcine coronary artery endothelial cells (PCEC) incorporated 20-[(3)H]HETE primarily into the sn-2 position of phospholipids through a coenzyme A-dependent process. The incorporation was reduced by equimolar amounts of arachidonic, eicosapentaenoic or 8,9-epoxyeicosatrienoic acids, but some uptake persisted even when a 10-fold excess of arachidonic acid was available. The retention of 20-[(3)H]HETE increased substantially when methyl arachidonoyl fluorophosphonate, but not bromoenol lactone, was added, suggesting that a Ca(2+)-dependent cytosolic phospholipase A(2) released the 20-HETE contained in PCEC phospholipids. Addition of calcium ionophore A23187 produced a rapid release of 20-[(3)H]HETE from the PCEC, a finding that also is consistent with a Ca(2+)-dependent mobilization process. PCEC also converted 20-[(3)H]HETE to 20-carboxy-arachidonic acid (20-COOH-AA) and 18-, 16-, and 14-carbon beta-oxidation products. 20-COOH-AA produced vasodilation in porcine coronary arterioles, but 20-HETE was inactive. These results suggest that the incorporation of 20-HETE and its subsequent conversion to 20-COOH-AA in the endothelium may be important in modulating coronary vascular function.
Kaduce
Terry L
TL
Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA.
Fang
Xiang
X
Harmon
Shawn D
SD
Oltman
Christine L
CL
Dellsperger
Kevin C
KC
Teesch
Lynn M
LM
Gopal
V Raj
VR
Falck
J R
JR
Campbell
William B
WB
Weintraub
Neal L
NL
Spector
Arthur A
AA
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D000001:Calcimycin / Q000494:pharmacology; D003331:Coronary Vessels / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism*; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism*; D007476:Ionophores / Q000494:pharmacology; D013552:Swine; D013997:Time Factors
D006893:Hydroxyeicosatetraenoic Acids; D007476:Ionophores; D000001:Calcimycin; C055987:20-hydroxy-5,8,11,14-eicosatetraenoic acid