Induction of cyclooxygenase-2 in thick ascending limb cells by adrenalectomy.
Induction of cyclooxygenase-2 in thick ascending limb cells by adrenalectomy.
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发表时间：
2001-04
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通讯作者：
C. Vio;S. An;C. Céspedes;J. Mcgiff;N. Ferreri
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作者：
C. Vio;S. An;C. Céspedes;J. Mcgiff;N. Ferreri
肾上腺切除（ADX）和假手术大鼠分别给予地塞米松（DEX）或载药。采用肾组织进行形态学分析、环氧化酶-2 （COX-2）蛋白表达、mRNA积累及COX-2活性测定。在未经治疗或假手术的大鼠中，在一个小管上皮细胞亚群中观察到COX-2蛋白（30%的TAL细胞表达COX-2，其方式与COX-2阳性TAL细胞向髓质的募集一致）。用DEX治疗ADX大鼠，使cox -2阳性细胞数量减少到假手术或完整大鼠的水平。ADX增加了COX-2 mRNA的积累，DEX部分减弱了COX-2 mRNA的积累。皮质微粒体的Western blot分析显示，与ADX/ dex处理、假手术或完整的大鼠相比，ADX大鼠的COX-2表达显著增加。与假手术大鼠相比，COX-2蛋白表达的增加与ADX大鼠获得的皮质微粒体形成的前列腺素E(2)增加两倍有关。结论是，ADX诱导酶活性COX-2的表达，使表达发生在皮质TAL中，并以确定的模式向外髓TAL进行。这表明，ADX诱导TAL细胞在基础状态下不表达COX-2蛋白。
Adrenalectomized (ADX) and sham-operated rats received either dexamethasone (DEX) or vehicle. Renal tissue was used for morphologic analysis, assessment of cyclooxygenase-2 (COX-2) protein expression and mRNA accumulation, and quantitation of COX-2 activity. In untreated or shamoperated rats, COX-2 protein was observed in a subset of tubular epithelial cells (30% of TAL cells expressed COX-2 in a manner consistent with recruitment of COX-2-positive TAL cells toward the medulla. Treatment of ADX rats with DEX reduced the number of COX-2-positive cells to that observed in sham-operated or intact rats. COX-2 mRNA accumulation was increased by ADX and partially attenuated by treatment with DEX. Western blot analysis of cortical microsomes revealed a substantial increase in COX-2 expression in ADX rats, compared with ADX/DEX-treated, sham-operated, or intact rats. The increase in COX-2 protein expression was associated with a twofold increase in prostaglandin E(2) formation by cortical microsomes obtained from ADX rats, compared with sham-operated rats. It is concluded that ADX induces expression of enzymatically active COX-2, such that expression occurs in the cortical TAL and proceeds in a defined pattern toward the outer medullary TAL. It is suggested that ADX induces expression of TAL cells that, in the basal state, do not express COX-2 protein.