Glucagon is a 29-amino acid peptide hormone secreted from the pancreatic alpha cells with a powerful stimulatory effect on hepatic glucose production acting to increase plasma glucose levels. Glucagon is best known as the counter-regulatory hormone to insulin, and normal glucose homeostasis depends largely on the balanced secretion of insulin and glucagon from the pancreatic beta and alpha cells, respectively.The regulation of glucose metabolism by glucagon is mediated by its direct action on the peripheral tissues such as the liver and also by the brain. Glucagon is also released postprandially in a transient manner, which was shown to be involved in inhibition of food intake via reduction of meal size.