As a counterregulatory hormone for insulin, glucagon plays a critical role in maintaining glucose homeostasis in vivo. It is well known that intramuscular glucagon administration stimulates growth hormone (GH), adrenocorticotropic hormone (ACTH) and cortisol release in humans. Recently, it has been shown that glucagon induces a remarkable decrease in ghrelin levels. The mechanisms underlying this effect are unclear and the role of changes in glucose, insulin, glucagon-like peptide-1 (GLP-1) and catecholamines are widely discussed. The aim of the present study is to further evaluate the effect of glucagon on ghrelin secretion and the possible role of the above mentioned factors in mediating this effect.