NRG4 and obesity due to melanocortin 4 receptor deficiency: Adipose tissue is a key “fuel” reservoir in the body and regulates various physiological processes through adipokines, including appetite production, fat distribution, insulin sensitivity changes, and inflammatory chemotactic responses.[5] Adipokines are widely used tools for treating obesity due to their relative stability and ease of supply.[6] Neuregulin 4 (Nrg4), a new type of adipokines mainly produced in white and brown adipose tissues, is closely associated with energy balance and glycolipid metabolism.