Minireview: 3-Iodothyronamine (T(1)AM): A New Player on the Thyroid Endocrine Team?

3-Iodothyronamine (T(1)AM) is an endogenous compound with chemical features that are similar to thyroid hormone. T(1)AM has a carbon skeleton identical to that of T-4 and contains a single carbon-iodine bond. Theoretically, T(1)AM could be produced from T-4 by enzymatic decarboxylation and deiodination. Recent studies show that T(1)AM and higher iodinated thyronamines are subject to similar metabolic processing as iodothyronines such as T-4, suggesting a biological linkage between iodothyronines and iodothyronamines. In addition, single doses of T(1)AM administered to rodents induce a hypometabolic state that in certain ways resembles hibernation and is opposite to the effects of excess T-4. This review will discuss the latest developments on this recently discovered thyroid hormone derivative. (Endocrinology 150: 1108-1111, 2009)