99mTc-pertechnetate uptake in parotid acinar cells by the Na+/K+/Cl- co-transport system.

Abstract

""Tc-Pertechnetate ("'rcO) has widespread clinical use in the diagnosis and evaluation of dysfunctions in many different tissues. However, despite the broad clinical application of this radionuclide, very little is known about the mechanism by which ""TcOi enters a cell. We report evidence here that ""'TcO4shares the Na+/K+/Cl co-transport system localized to the basolateral membrane of rat parotid acinar cells. " TcO. uptake by these cells was quite rapid (t1/2 30 s), was completely inhibited by the loop diuretics furosemide and bumetanide, and was markedly dependent on the presence of Na', K+, and Oin the extracellular medium. Relative to uptake measured in the presence of physiological extracellular salt concentrations (Hanks' salts), "'TcOj 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 ""'TcO uptake resulted. These observations provide strong evidence that "'TcO4 can substitute for G-as a substrate for the Na+/K+/Cl-co-transporter and indicate that "'TcO4 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.

Morphometric and Functional Changes of Salivary Gland Dysfunction After Radioactive Iodine Ablation in a Murine Model

“…NIS is an integral plasma membrane glycoprotein that mediates the active transport of iodide ions into thyroid follicular cells (11-13) and thus plays a major role in RAI uptake. As a result, RAI can accumulate in SG tissues because of the action of native NIS (14,15).…”

Sialendoscopy for Patients with Radioiodine-Induced Sialadenitis and Xerostomia

“…The iodine uptake may be mediated by the sodium-iodide symporter, which is expressed in various extrathyroidal tissues, including the ductal cells of the salivary glands (9,10). Serous acini have shown increased uptake of RAI compared to mucinous acini, resulting in injury of the parotid glands more commonly than the submandibular and sublingual glands (2,11).…”

Scintigraphic Evaluation of Lacrimal Glands Using a Rabbit Experimental Model

“…It has recently been proven that the 99m Tc-pertechnetate uptake of salivary glands reflects the functional activity of the Na + /K + /Cl co-transport mechanism in the acinar cells [8]. Thus, this radiotracer has been used as a surrogate parameter of salivary gland function to assess the secretory activity of these glands using gamma scintigraphy.…”