Usefulness of Tc-99m-d,l-HMPAO for estimation of GSH content in tumor tissues

To investigate whether [Tc-99m]-hexamethyl propyleneamine oxime ([Tc-99m]-H MPAO) is applicable for evaluating glutathione (GSH) localization in tumor, the difference of distribution between [Tc-99m]-d,l- and meso-HMPAO was st udied using a mouse tumor model. Biodistribution of [Tc-99m]-d,l- or meso H MPAO was studied in GSH depleted and control Ehrlich tumor-bearing mice. GS H levels in tumors in GSH depleted and control mire were measured in anothe r set of mice. The uptake of [Tc-99m]-d,l-HMPAO in tumor was significantly decreased by the diethyl maleate (DEM) treatment. On the other hand, the DE M treatment increased the accumulation of [Tc-99m]-meso-HMPAO in tumor. Mea nwhile, the content of GSH was lowest in tumor among the tissues tested and decreased in a manner similar to other tissues on preloading of DEM. [Tc-9 9m]-d,l-HMPAO may be useful for estimating the GSH status in a certain tumo r and thereby contribute to the diagnosis of anticancer therapy. NUCL MED B IOL 27;6:577-580, 2000. (C) 2000 Elsevier Science Inc. All rights reserved.