Ghrelin immunoexpression in the pituitaries of patients with anorexia nervosa

Ghrelin is involved in the regulation of energy balance. As an orexigenic hormone, it stimulates appetite, increases food intake and leads to obesity. Blood ghrelin levels are significantly elevated in patients with anorexia nervosa, an eating disorder characterized by starvation and reduced body weight. We investigated ghrelin immunoexpression in 29 pituitaries of anorexia nervosa patients who passed away. Double Immunostaining was also undertaken to determine which cell type was expressing both the adenohypophysial hormone and ghrelin. In autopsy obtained adenohypophyses, ghrelin mainly localized in somatotrophs and to a lesser extent in corticotrophs and gonadotrophs. Compared to adenohypophyses of patients who did not suffer from anorexia nervosa, ghrelin immunoexpression was not depleted; cytoplasmic immunopositivity was strong in many somatotrophs and to a lesser extent in corticotrophs and gonadotrophs. Ghrelin accumulated along the nerve fibers in the posterior lobe and pituitary stalk. It may be that in patients with anorexia nervosa, ghrelin is released from the hypothalamic neurons in excess and transported via the pituitary stalk and deposited in the posterior lobe.