Role of 20-hydroxyeicosatetraenoic acid (20-HETE) in altering sodium excretion in hypothyroid rats.

NOWICKI S; GUREVICH JM; SANCHEZ ALBERTI A; GONZALEZ D; ROMAN RJ

Baltimore

Conferencia; The 12th International Winter Eicosanoid Conference; 2010

The Eicosanoid Research Association

Role of 20-hydroxyeicosatetraenoic acid (20-HETE) in altering sodium excretion in hypothyroid rats Susana Nowicki, Juan M. Gurevich, Andres Sanchez Alberti, Daniel Gonzalez, Richard J. Roman. Center for Endocrinological Research (CEDIE-CONICET), Gallo 1360, 1425 Buenos Aires, Argentina; and Department of Pharmacology, University of Mississippi Medical Center, 2500 North State Street, Jackson,  MS 39216-4505 The present study examines the effects of thyroidectomy (TX) on the expression of CYP4A in the proximal tubule (PT), and sodium excretion following volume expansion in rats. We found that the expression of CYP4A2 mRNA and CYP4A protein increased significantly following TX, however the production of 20-HETE by PT cells did not increase. Urine flow and sodium excretion increased by 2 and 4 fold respectively following TX and this was associated with inhibition of sodium reabsorption in the distal rather than the proximal tubule. The natriuretic effect of TX was reversed by administration of T3 and by blockade of the synthesis of both EETs and 20-HETE with ABT (50 mg/Kg, ip). These results indicate that the natriuretic response to TX is not mediated by elevations in the production of 20-HETE and inhibition of sodium transport in the proximal tubule, but may be associated with upregulation of the production of 20-HETE or/and EETs, and inhibition of sodium transport in the distal nephron .