QS Study

Regulation of Insulin Secretion

The primary stimulus for insulin secretion is the beta-cell response to changes in ambient glucose. Impaired or insufficient insulin secretion results in diabetes mellitus. Insulin secretion is regulated by the followings –

(1) Blood glucose (By negative feedback mechanism): Glucose is transported into beta cells through facilitated diffusion of GLUT2 glucose transporters. Insulin is secreted mainly in response to glucose, while other nutrients such as free fatty acids and amino acids can enlarge glucose-induced insulin secretion.

  • ↑ Blood glucose
  • (+) β- cells
  • Insulin release
  • ↓Blood glucose
  • ↓Insulin secretion

(2) Amino acids: Addition of excess amino acids stimulates insulin secretion.

(3) Gastrointestinal hormones: Some GI tract local hormones gastrin, secretin, GIP, CCK- Pz etc. moderately Stimulate insulin secretion.

(4) Some other hormones of autonomic nervous system: Glucagon, growth hormone, cortisol and to a lesser extent, progesterone and estrogen either directly stimulate insulin secretion or potentiate the glucose stimulus for insulin secretion. In general, glucose triggers insulin secretion while other factors can amplify or inhibit the amount of insulin secreted in response to glucose.

(5) Parasympathetic stimulation: Stimulation of the parasympathetic nerves to the pancreas can increase insulin secretion in some conditions.

(6) Local factor (Somatostatin):

  • ↑Somatostatin
  • ↓Insulin secretion.