Subject(s)
Antithyroid Agents/chemical synthesis , Symporters/antagonists & inhibitors , Aniline Compounds/chemical synthesis , Aniline Compounds/chemistry , Aniline Compounds/pharmacology , Animals , Antithyroid Agents/chemistry , Antithyroid Agents/pharmacology , Biological Transport/drug effects , Cells, Cultured , Drug Design , Inhibitory Concentration 50 , Rats , Structure-Activity Relationship , Symporters/metabolismABSTRACT
The standard assay for sodium iodide symporter (NIS) function is based on the measurement of radioiodide uptake ((125)I) in NIS-expressing cells. However, cost and safety issues have limited the method from being used widely. Here we describe a simple spectrophotometric assay for the determination of iodide accumulation in rat thyroid-derived cells (FRTL5) based on the catalytic effect of iodide on the reduction of yellow cerium(IV) to colorless cerium(III) in the presence of arsenious acid (Sandell-Kolthoff reaction). The assay is fast and highly reproducible with a Z' factor of 0.70. This procedure allows the screening of more than 800 samples per day and can easily be adapted to robotic systems for high-throughput screening of NIS function modulators. Using this method, the potency of several known inhibitors of NIS function was evaluated in a single day with high accuracy and reliability. Measured IC(50) values were essentially identical to those determined using Na(125)I.
