The chemical structure, target-cells, mechanism of action, physiologic effects, regulation of secretion of glucagon
The chemical structure: It is peptide consisting of 29 amino acids. It is formed in A-cells of pancreas. It is also formed in some cells of intestinal mucosa.
Target-cells: are cells of liver, muscles, adipose tissue, myocardium, B-cells of pancreas
Mechanism of action: 1-st through c.AMP
Physiologic effects:
This hormone increases the level of glucose in blood plasma due to gluconeogenesis from lipids (from glycerol). The glycogenolysis and lipolysis are increased too. But effect on glycogenolysis lasts during short time. Therefore gluconeogenesis is a main reason of increase of glucose in blood plasma.
Regulation of secretion high level of glucose decreases glucagon secretion. Low level of glucose in blood plasma increases one.