Cytochrome P450-dependent arachidonic acid metabolites, 19- 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.