Hepoxilin A, hydroxyepoxide metabolite of arachidonic acid, stimulates transport of 45Ca across the guinea pig visceral yolk sac.
The effect of hepoxilin A, a newly isolated hydroxyepoxide metabolite of arachidonic acid, on calcium transport across the visceral yolk sac membrane of the guinea pig was investigated in vitro in Ussing chambers. While 1-14C-labelled hepoxilin A itself was not transported across the membrane, it increased the rate of transport of calcium toward the side to which hepoxilin A was added. The degree of increase in calcium transport was similar whether hepoxilin A was added to the maternal side or to the fetal side of the membrane. The observed effect was dependent on the concentration of hepoxilin A over a narrow range (0.5-1.0 X 10(-6) M). It was also dependent on the time of incubation reaching maximal effect by 25 min. We have recently observed that hepoxilin A is formed from platelet-derived 12-hydroperoxyeicosatetraenoic acid (12-HPETE) through hemin and hemoglobin catalysis as well as during perifusion of 12-HPETE through isolated pancreatic islets. The present study suggests that hepoxilin A, if formed in vivo, could play a role in the mobilization of calcium.
D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism* / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D011247:Pregnancy; D015017:Yolk Sac / Q000378:metabolism*
D001095:Arachidonic Acids; D016718:Arachidonic Acid; C038243:8-hydroxy-11,12-epoxyeicosa-5,9,14-trienoic acid; D015126:8,11,14-Eicosatrienoic Acid; D002118:Calcium