We assume that the effects of T3 administration on the expression of AQP4 observed in the present study are not attributable to the possible toxic effects of T3 on the brain or thyroid, given that the experimental protocols used to induce hyperthyroidism in animals involve administration of this hormone for approximately 14 consecutive days and at a dosage of 250 μg/kg (Drover and Agellon, 2004), which is considerably higher than the used in the present study. The gene discussed is AQP4; the disease is hyperthyroidism.