Expression of 5’-deiodinase in various thyroid tumors

5'-deiodination is an important pathway for the metabolism of T4 by determining its great role as a prohormone for T3. T4 is metabolized by two 5'-deiodinases: DI and DII which are encoded by different genes, regulated by different modes and expressed in various tissues. The aim of the present study was to examine DI and DII expression in health and in various human thyroid tumors. Eighteen thyroid specimens (10 from tumors and 8 from the intact thyroid tissues surrounding the nodes) were used. RNA isolated from the tissues by reserve transcription, followed by polymerase chain reaction (PCR) were transcribed to cDNA. Gel electrophoresis showed the bands corresponding to 177 b. p for DI and 796 b. p for DII. The experiments demonstrated that there were genes of both isoenzymes of 5 ’deiodinases in thyroid carcinoma tissues. Gel electrophoresis indicated the different expression of PCR products in different thyroid tumors for DI and DII at the level of mRNA.