Low dose 3-iodothyronamine increases acute lipolysis followed by protein catabolism in mouse

3-iodothyronamine (T1AM) is a recently discovered fast-acting thyroid hormone derivative. To date, the physiological effects of endogenousT1AM remain elusive, although there is increasing interest in its physiological function and pharmaceutical potential due to the role it plays in lipid and glucose metabolism (1.2).The present study monitored the effect of weeklong, daily, low dose T1AM administration on weight and metabolism in spontaneously overweight mice. Mice treated with exogenous T1AM (10 mg/Kg/day) lost 8.2% of their initial body weight by day 9 and regained only 1.8% of initial weight in the following 2 weeks, indicating lasting effects of T1AM on weight maintenance. Real-time analysis of exhaled 13CO2 by cavity ringdown spectroscopy (CRDS) detected increased lipolysis shortly after T1AM administration followed by a shift, later in the week, towards protein catabolism. Blood based metabolomics data obtained by nuclear magnetic resonance spectroscopy (NMR) were in agreement with the results from breath analysis, as indicated by the alterations found in key metabolites: valine, glycine, and 3-hydroxybutyrate. While this study begins to decode longer-term effects of T1AM on metabolism, additional studies with mildly feed restricted mice are currently underway to develop an appropriate dosing schedule for T1AM to be used as an effective weight loss and weight maintenance drug. References: Scanlan TS, Endogenous 3-Iodothyronamine (T1AM): More Than We Bargained For. J Clin Endocrinol Metab 2011, 96 (6), 1674-6. Dhillo WS, Bewick GA, White NE, Gardiner JV, Thompson EL, Bataveljic A, Murphy KG, Roy D, Patel NA, Scutt JN, Armstrong A, Ghatei MA, Bloom SR, The thyroid hormone derivative 3-iodothyronamine increases food intake in rodents. Diabetes Obes Metab 2009, 11 (3), 251-60.