1. Islets of Langerhans consists of three types of cells known as a-cells, β-cells and δ-cells.
2. α-cells secrete glucagon while β-cells secrete insulin. δ-cells secrete somatostatin.
3. The glucagon is a hyperglycemic hormone. It is a peptide hormone which acts mainly on the liver cells. Here it stimulates hepatocytes for glycogenolysis (i.e. breakdown of glycogen) leading to increased level of blood glucose (i.e. hyperglycemia).
4. It also stimulates gluconeogenesis (i.e. formation of glucose from non-carbohydrate sources). This in turn brings rise in blood glucose level or hyperglycemia.
5. Glucagon reduces the cellular glucose uptake and utilisation.
6. Insulin is also a peptide hormone, which plays a major role in maintenance of blood glucose level.
7. Insulin stimulates hepatocytes and adipocytes for cellular glucose uptake and utilization.
Therefore glucose from the blood decreases causing hypoglycemia. This hormone helps in the conversion of glucose to glycogen (i.e. glycogenesis) that occurs in target cells.
