Effects of 20-HETE on Na+ transport and Na+-K+-ATPase activity in the thick ascending loop of Henle

Ming Yu, Bernardo Lopez, Elisabete A. Dos Santos, John R. Falck, Richard J. Roman
2007 American Journal of Physiology. Regulatory Integrative and Comparative Physiology  
Previous studies have indicated that 20-hydroxyeicosatetraenoic acid (20-HETE) inhibits Na ϩ transport in the medullary thick ascending loop of Henle (mTALH), but the mechanisms involved remain uncertain. The present study compared the effects of 20-HETE with those of ouabain and furosemide on intracellular Na ϩ concentration ([Na ϩ ]i), Na ϩ -K ϩ -ATPase activity, and 86 Rb ϩ uptake, an index of Na ϩ transport, in mTALH isolated from rats. Ouabain (2 mM) increased, whereas furosemide (100 M)
more » ... creased, [Na ϩ ]i in the mTALH of rats. Ouabain and furosemide inhibited 86 Rb ϩ uptake by 91 and 30%, respectively. 20-HETE (1 M) had a similar effect as ouabain and increased [Na ϩ ]i from 19 Ϯ 1 to 30 Ϯ 1 mM. 20-HETE reduced Na ϩ -K ϩ -ATPase activity by 30% and 86 Rb ϩ uptake by 37%, but it had no effect on 86 Rb ϩ uptake or [Na ϩ ]i in the mTALH of rats pretreated with ouabain. 20-HETE inhibited 86 Rb ϩ uptake by 12% and increased [Na ϩ ]i by 19 mM in mTALH pretreated with furosemide. These findings indicate that 20-HETE secondarily inhibits Na ϩ transport in the mTALH of the rat, at least, in part by inhibiting the Na ϩ -K ϩ -ATPase activity and raising [Na ϩ ]i. cytochrome P-4504A; 20-hydroxyeicosatetraenoic acid; sodium-potassium-adenosinetriphosphatase; medullary thick ascending loop of
doi:10.1152/ajpregu.00791.2006 pmid:17303679 fatcat:j4xb6ymjxbceho3v6ny5or4iai