3-Iodothyronamine (T₁AM) is an endogenous thyronamine. T₁AM is a high-affinity ligand for the trace amine-associated receptor TAAR1 (TAR1, TA1), a recently discovered G protein-coupled receptor. T₁AM is the most potent TAAR1 agonist yet discovered. Activation of TAAR1 by T₁AM results in the production of large amounts of cAMP. This effect is coupled with decreased body temperature and cardiac output. Wu et al have pointed out that this relationship is not typical of the endocrine system, indicating that TAAR1 activity may not be coupled to G-proteins in some tissues, or that T₁AM may interact with other receptor subtypes.