ARO activity has been detected in adipose tissue [47], and several studies have demonstrated a potentially important role for this enzyme in obesity, central fat accumulation, and metabolic syndrome (MetS) [48], through estrogen receptors (ERs) and ARs, which are abundantly expressed in the adipocyte and share related functions to suppress adipose tissue accumulation and improve insulin sensitivity [49]. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.