Ovariectomy enhances renal cortical expression and function of cyclooxygenase-2.

Background: Cyclooxygenase-2 (COX-2) inhibitors are used as analgesics in postmenopausal women, who develop edema and require a salt-restricted diet. This study was performed to determine the renal expression of COX-2 and on COX-2-dependent regulation of renal blood flow (RBF) in ovariectomized rats.

Methods: Sprague-Dawley rats were divided into 4 groups: sham-operated rats fed a normal-salt diet (Sh+NS) or a low-salt diet (Sh+LS), and bilaterally ovariectomized rats fed a normal-salt diet (Ox+NS) or a low-salt diet (Ox+LS) (N= 6 in each group). Estrogen replacement therapy was performed on other ovariectomized rats. A renal clearance study was performed in anesthetized animals.

Results: Ovariectomy increased renal cortical COX-2 expression independently of dietary salt intake (Sh+NS
Conclusion: Estrogen-dependent COX-2 expression plays an important role in the RBF regulation in female rats.