It has been reported that adipose tissue regulates feeding behavior by secreting adipokines like leptin and adiponectin30,39 or by releasing metabolites such as fatty acids.40 However, there were no changes in the circulating levels of these molecules before the onset of obesity in female Adipoq-TrkB CKO mice. Here, NTRK2 is linked to obesity due to melanocortin 4 receptor deficiency.