TC-99M-PERTECHNETATE UPTAKE IN PAROTID ACINAR-CELLS BY THE NA+/K+/CL- COTRANSPORT SYSTEM
TC-99M-PERTECHNETATE UPTAKE IN PAROTID ACINAR-CELLS BY THE NA+/K+/CL- COTRANSPORT SYSTEM
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DOI：
10.1172/jci112954
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发表时间：
1987-05-01
影响因子：
15.9
通讯作者：
BAUM, BJ
中科院分区：
文献类型：
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作者：
HELMAN, J;TURNER, RJ;BAUM, BJ
99mTc-Pertechnetate (99mTcO4-) 在许多不同组织的诊断和评估以及功能障碍方面具有广泛的临床应用。然而，尽管这种放射性核素具有广泛的临床应用，但人们对 99mTcO4- 进入细胞的机制知之甚少。我们在此报告证据表明 99mTcO4- 共享位于大鼠腮腺腺泡细胞基底外侧膜的 Na+/K+/Cl- 协同转运系统。这些细胞对 99mTcO4- 的吸收相当快（t1/2 约 30 秒），被袢利尿剂呋塞米和布美他尼完全抑制，并且明显依赖于细胞外介质中 Na+、K+ 和 Cl- 的存在。相对于在生理细胞外盐浓度（汉克斯盐）存在下测量的吸收，99mTcO4-吸收被钠替代抑制80%，通过钾替代抑制50%。当 Cl- 被生理惰性阴离子葡萄糖酸盐取代时，99mTcO4- 的吸收得到三倍的刺激。这些观察结果提供了强有力的证据，表明 99mTcO4- 可以替代 Cl- 作为 Na+/K+/Cl- 协同转运蛋白的底物，并表明唾液腺（例如，如唾液闪烁扫描所见）以及可能由多种其他组织摄取 99mTcO4- 反映了这种协同转运机制的功能活性。
99mTc-Pertechnetate (99mTcO4-) has widespread clinical use in the diagnosis and evaluation and dysfunctions in many different tissues. However, despite the broad clinical application of this radionuclide, very little is known about the mechanism by which 99mTcO4- enters a cell. We report evidence here that 99mTcO4- shares the Na+/K+/Cl- co-transport system localized to the basolateral membrane of rat parotid acinar cells. 99mTcO4- uptake by these cells was quite rapid (t1/2 .apprx. 30 s), was completely inhibited by the loop diurectics furosemide and bumetanide, and was markedly dependent on the presence of Na+, K+, and Cl- in the extracellular medium. Relative to uptake measured in the presence of physiological extracellular salt concentrations (Hanks'' salts), 99mTcO4- uptake was inhibited 80% by sodium replacement and 50% by potassium replacement. When Cl- was replaced with the physiologically inert anion gluconate a threefold stimulation in 99mTcO4- uptake resulted. These observations provide strong evidence that 99mTcO4- can substitute for Cl- as a substrate for the Na+/K+/Cl- co-transporter and indicate that 99mTcO4- uptake by salivary glands (e.g., as seen with salivary scintiscans), and possibly by a variety of other tissues, reflects the functional activity of this co-transport mechanism.