GHRL and Anorexia: Accordingly, increased plasma levels of ghrelin, e.g., in AN patients and in animal models of anorexia (Figure 1), may signify ghrelin’s inability to form stable immune complexes with IgG and, hence, may result in a functional deficiency of the ghrelin signaling or “ghrelin resistance.” Such explanation may appear at first glance as paradoxical, but it gains further support from the corroborating data revealing an enhancing role of IgG in signaling by other peptide hormones such as α-MSH (37, 38).