Even though Dio2 expression and activity are not modified under basal conditions by a hypercaloric diet, as observed in our first experiment (Table 1) and other studies (62, 63), the combination of obesity with acute stress may have altered MBH-Dio2 expression, since this enzyme is susceptible to various types of stimuli (47, 90–92). This evidence concerns the gene DIO2 and obesity due to melanocortin 4 receptor deficiency.