Exogenous 3-Iodothyronamine (T 1 AM) Can Affect Phosphorylation of Proteins Involved on Signal Transduction Pathways in In Vitro Models of Brain Cell Lines, but These Effects Are Not Strengthened by Its Catabolite, 3-Iodothyroacetic Acid (TA 1 ).

T 1 AM, a derivative of thyroid hormones, and its major catabolite, TA 1 , produce effects on memory acquisition in rodents. In the present study, we compared the effects of exogenous T 1 AM and TA 1 on protein belonging to signal transduction pathways, assuming that TA 1 may strengthen T 1 AM's effects in brain tissue. A hybrid line of cancer cells of mouse neuroblastoma and rat glioma (NG 108-15), as well as a human glioblastoma cell line (U-87 MG) were used. We first characterized the in vitro model by analyzing gene expression of proteins involved in the glutamatergic cascade and cellular uptake of T 1 AM and TA 1 . Then, cell viability, glucose consumption, and protein expression were assessed. Both cell lines expressed receptors implicated in glutamatergic pathway, namely Nmdar1, Glur2, and EphB2, but only U-87 MG cells expressed TAAR1. At pharmacological concentrations, T 1 AM was taken up and catabolized to TA 1 and resulted in more cytotoxicity compared to TA 1 . The major effect, highlighted in both cell lines, albeit on different proteins involved in the glutamatergic signaling, was an increase in phosphorylation, exerted by T 1 AM but not reproduced by TA 1 . These findings indicate that, in our in vitro models, T 1 AM can affect proteins involved in the glutamatergic and other signaling pathways, but these effects are not strengthened by TA 1 .