3-Iodothyronamine is considered as a derivate of thyroid hormone as a result of 
enzymatic deiodination and decarboxylation. The physiological role of 
thyronamine (T1AM) is not known. The aim of this study was to analyze the 
metabolic response to T1AM in the Djungarian hamster Phodopus sungorus. We 
measured the influence of T1AM (50 mg/kg) on metabolic rate (VO(2)), body 
temperature (T (b)) and respiratory quotient (RQ) in this species and in BL/6 
mice. T1AM treated hamsters as well as the mice showed a rapid decrease in VO(2) 
and T (b), accompanied by a reduction of RQ from normal values of about 
approximately 0.9 to approximately 0.70 for several hours. This indicates that 
carbohydrate utilisation is blocked by the injection of T1AM and that metabolic 
pathways are rerouted from carbohydrate to lipid utilisation in response to 
T1AM. This assumption was further supported by the observation that the 
treatment of T1AM caused ketonuria and a significant loss of body fat. Our 
results indicate that T1AM has the potential to control the balance between 
glucose and lipid utilisation in vivo.