Amongst these endocrine factors, neuregulin 4 (Nrg4) from the epidermal growth factor family of extracellular ligands which signal via ErbB receptors of tyrosine kinases is gaining unwavering attention because of its potential modulatory role during the pathogenesis of obesity and other various metabolic diseases [24,25]. This evidence concerns the gene NRG4 and obesity due to melanocortin 4 receptor deficiency.