CYTOCHROME-P450-DEPENDENT ARACHIDONIC-ACID METABOLITES, 19-HYDROXYEICOSATETRAENOIC AND 20-HYDROXYEICOSATETRAENOIC ACIDS, ENHANCE SODIUM-POTASSIUM ATPASE ACTIVITY IN VASCULAR SMOOTH-MUSCLE

Several cytochrome P450-dependent arachidonic acid metabolites have been shown to affect Na+, K+-ATPase activity. In the present study, we tested the effect of α and ω - 1-hydroxylated products, i.e., 19- and 20-hydroxyeicosatetraenoic acids (19- and 20-HETE), on the K-induced relaxation in rat aortic rings. 19-HETE and 20-HETE increased the magnitude of the potassium-induced relaxation in a dose-dependent fashion (10-7-10-5 M). The inhibitory effect of ouabain on the potassium-induced relaxation was reversed by both 19- and 20-HETE. In addition, indomethacin fully inhibited the stimulatory effect of 19- and 20-HETE on relaxation induced by potassium. Vascular ouabainsensitive 86Rb uptake was also increased by 19- and 20-HETE. These observations suggest that 19- and 20-HETE stimulate vascular Na+, K+-ATPase via their conversion by cyclooxygenase to prostaglandin-like material. © 1990 Raven Press, Ltd., New York.