Role of 20-HETE in elevating loop chloride reabsorption in Dahl SS/Jr rats.
In vivo tubular perfusion experiments were performed in normotensive Dahl salt-sensitive (SS/Jr) and salt-resistant (SR/Jr) rats maintained from birth on a low salt (0.4% NaCl) diet to examine the role of 20-HETE in elevating loop Cl- transport in SS/Jr rats. Chloride reabsorption in the loop of Henle was significantly greater in SS/Jr than in SR/Jr rats (77 +/- 2% versus 57 +/- 3% of the perfused Cl- load). When the renal metabolism of arachidonic acid by P450 was blocked by the addition of 17-octadecynoic acid (10 micromol/L) to the perfusate, loop Cl- transport increased in SR/Jr rats to 70 +/- 2% of the delivered Cl- load, but it had no effect in SS/Jr rats. Conversely, addition of 20-HETE (10 micromol/L) to the perfusate lowered loop Cl- transport in S rats to 60 +/- 2% of perfused Cl- load, but it had no effect in SR/Jr rats. Addition of another endogenously formed HETE to the perfusate, 15-HETE (20 micromol/L), had no effect on Cl- reabsorption in the loop of Henle of SS/Jr rats. These findings indicate that endogenously produced P450 metabolites of arachidonic acid regulate Cl- transport in the loop of Henle of the rat in vivo and support the view that a diminished production of 20-HETE in the outer medulla of SS/Jr rats contributes to the elevation in loop Cl- transport and the resetting of the pressure-natriuresis relation in these animals.
Zou
A P
AP
Department of Physiology, Medical College of Wisconsin, Milwaukee, 53226, USA.
Drummond
H A
HA
Roman
R J
RJ
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002712:Chlorides / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006893:Hydroxyeicosatetraenoic Acids / Q000494:pharmacology*; D006973:Hypertension / Q000378:metabolism*; D008138:Loop of Henle / Q000378:metabolism*; D051381:Rats
D002712:Chlorides; D006893:Hydroxyeicosatetraenoic Acids; C055987:20-hydroxy-5,8,11,14-eicosatetraenoic acid; D003577:Cytochrome P-450 Enzyme System