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- Title
Ovariectomy enhances renal cortical expression and function of cyclooxygenase-2.
- Authors
Tada, Yuko; Ichihara, Atsuhiro; Koura, Yukako; Okada, Hirokazu; Kaneshiro, Yuki; Hayashi, Matsuhiko; Saruta, Takao
- Abstract
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<Ox+N; Sh+LS<Ox+LS). Inhibition of COX-2 by NS398 reduced the urinary excretion of 6-keto-prostaglandin F1α in all 4 groups, although the reduction was greater in the Ox+LS group than in the Ox+NS and Sh+LS groups, which in turn had a greater reduction than the Sh+NS group. RBF significantly decreased in every group except the Sh+NS group, but no effect on blood pressure, inulin clearance, or urinary sodium excretion was seen. The decrease in RBF was significantly greater in the Ox+LS group than in the Sh+LS and Ox+NS group. The decrease in RBF was dependent on cortical RBF in the Sh+LS and Ox+NS groups, and on both cortical and medullary RBF in the Ox+LS group. Estrogen replacement therapy reversed the ovariectomy-induced changes.Conclusion.Estrogen-dependent COX-2 expression plays an important role in the RBF regulation in female rats.
- Subjects
OVARIECTOMY; OVARIAN surgery; CYCLOOXYGENASE 2; CYCLOOXYGENASES; OXIDOREDUCTASES; SALT; KIDNEY diseases
- Publication
Kidney International, 2004, Vol 66, Issue 5, p1966
- ISSN
0085-2538
- Publication type
Article
- DOI
10.1111/j.1523-1755.2004.00983.x