Indeed, diet-induced obesity has been shown to result in cerebral ghrelin resistance in rodents, which was marked by the attenuated expression of hypothalamic GHS-R1α, NPY and AgRP as well as the loss of Fos-immunoreactivity in ARC neurons in response to peripheral and central injections of AG (Briggs et al., 2010; Naznin et al., 2015). This evidence concerns the gene GHSR and obesity due to melanocortin 4 receptor deficiency.