What are the four hormones secreted by the islets of Langerhans?
May 17, 2023
Source: Cainiu Health
Dr. Pan Yongyuan
Introduction
Under normal conditions, the pancreas secretes four main hormones: insulin, glucagon, pancreatic polypeptide, and somatostatin. Insulin is one of the most important hormones produced by the pancreas. It is secreted by the beta cells of the islets of Langerhans and plays a crucial role in blood glucose regulation. The primary function of insulin is to promote the uptake and utilization of glucose by cells, thereby lowering blood glucose levels.
Under normal circumstances, the pancreas secretes four main hormones: insulin, glucagon, pancreatic polypeptide, and somatostatin. A detailed analysis is as follows:
1. Insulin
Insulin is one of the most important hormones produced in the pancreatic islets. It is secreted by beta (β) cells of the islets and plays a key role in blood glucose regulation. The primary function of insulin is to promote the uptake and utilization of glucose by cells, thereby lowering blood glucose levels. Insulin also enhances the absorption of fatty acids and amino acids and promotes energy storage in the body.
2. Glucagon
Glucagon is secreted by alpha (α) cells of the pancreatic islets. Its actions oppose those of insulin. Glucagon promotes the breakdown of glycogen in the liver and its conversion into glucose, thus increasing blood glucose levels. Glucagon also stimulates the breakdown of fatty acids to enhance energy supply.
3. Pancreatic Polypeptide
Pancreatic polypeptide is a hormone secreted by delta (δ) cells within the pancreatic islets. It primarily participates in regulating gastrointestinal functions, including inhibition of gastric acid secretion and modulation of gastrointestinal motility. Additionally, pancreatic polypeptide plays a regulatory role in pancreatic islet function, helping modulate the secretion of insulin and glucagon.
4. Somatostatin
Somatostatin is secreted by delta (δ) cells in the pancreatic islets as well as other neuroendocrine cells. Within the islets, it exerts an inhibitory effect, suppressing the secretion of both insulin and glucagon, thereby helping regulate blood glucose levels. Furthermore, somatostatin modulates the secretion of other endocrine glands, including inhibiting gastric acid secretion and gallbladder contraction.
These pancreatic islet hormones interact with each other to maintain the body's energy balance through the regulation of blood glucose levels. If abnormal hormone secretion from the islets occurs, prompt medical evaluation and treatment are recommended.
