Synthesis of [¹²⁵I]-, [²H]-, and [ ³H]-labeled 3-iodothyronamine (T₁AM)

3-Iodothyronamine (T₁AM) is a novel metabolite of thyroid hormone. In HEK-293 cells expressing an orphan G-protein coupled receptor, the trace amine receptor, T₁AM, potently increased cAMP accumulation. In mice, T₁AM rapidly induced hypothermia and bradycardia within minutes of administration. These results suggest the existence of a new signaling pathway, the stimulation of which leads to rapid physiological and behavioral consequences. Isotope-labeled T₁AM derivatives would be useful to study the biology and pharmacology of T₁AM. Herein we describe efficient syntheses of [¹²⁵I]-, [²H]-, and [ ³H]-T₁AM.