Effect of gonadectomy on the metabolism of arachidonic acid in isolated kidney of a rat model of metabolic syndrome

Influence of sex on arachidonic acid metabolism, a pathway involved in the link between metabolic syndrome (MS) and renal damage, was studied in isolated perfused kidney. Metabolic syndrome was induced by feeding 30% sucrose solution for 24 weeks to intact and gonadectomized female (Ovx) and male (Cas) rats. Systolic blood pressure, albuminuria, as well as prostaglandin E2 and thromboxane B2 from urine and perfusate increased in MS male and MS ovariectomized females; castration reduced them in MS males. Perfusion of arachidonic acid in kidneys from MS males increased perfusion pressure compared with controls. No difference appeared in perfusion pressure between control and MS females. Castration diminished perfusion pressure in MS; the opposite was observed in Ovx MS. Perfusion with arachidonic acid plus indomethacin decreased perfusion pressure in MS male kidneys and in Cas MS. In Ovx MS, arachidonic acid plus indomethacin decreased perfusion pressure, but not in female control, MS, and Ovx control. Increase in perfusion pressure with arachidonic acid in both male MS and Ovx MS was related to cyclooxygenase (COX)-1 and COX-2 overexpression in kidney. Castration reduced the expression of COX-1 and COX-2 in MS to control levels. The results suggest that the alteration in arachidonic acid metabolism associated with changes in the expression of COX-1 and COX-2 induced by sucrose intake, and influenced by sex hormones, may contribute to renal damage. © 2010 Elsevier Inc. All rights reserved.