Also, iodothyronine deiodinases (type 2 y 3; DIO2 and DIO3, respectively) respond to seasonal changes in photoperiod-driven melatonin secretion and govern peri-hypothalamic catabolism of the prohormone thyroxine (T4). In long summer days, the production of hypothalamic T3 increase due to DIO-2-mediated conversion of T4 to the biologically active hormone. This process allows to active anabolic neuroendocrine pathways that maintain reproductive competence and increase body weight. However, during the adaptation to reproductively inhibitory photoperiods, the levels of T3 decrease due to peri-hypothalamic DIO3 expression that catabolizes T4 and T3 into receptor inactive amines.
Also, iodothyronine deiodinases (type 2 y 3; DIO2 and DIO3, respectively) respond to seasonal changes in photoperiod-driven melatonin secretion and govern peri-hypothalamic catabolism of the prohormone thyroxine (T4). In long summer days, the production, of hypothalamic T3 increas.e due to DIO-2-mediated conversion of T4 to the biologically active hormone. This process allows to active anabolic neuroendocrine pathways that maintain reproductive competence and increase body weight. However, during the adaptation to reproductively inhibitory photoperiods the levels of T3 decrease due to peri-hypothalamic DIO3 expression that catabolizes T4 and T3 into receptor inactive amines