gastrineritys

Gastrin is a peptide hormone primarily produced by G cells in the stomach and upper small intestine. It plays a crucial role in regulating gastric acid secretion, which is essential for digestion. Gastrin is released in response to the presence of food in the stomach, particularly proteins and amino acids, and stimulates parietal cells to produce hydrochloric acid (HCl).

The secretion of gastrin is tightly controlled by feedback mechanisms. High levels of gastric acid inhibit further gastrin release through a negative feedback loop, while the presence of food and certain hormones, such as cholecystokinin (CCK), promote its secretion. Additionally, the vagus nerve, part of the parasympathetic nervous system, stimulates gastrin release, enhancing gastric motility and acid production.

Gastrin exists in multiple forms, including G-17, G-34, and G-14, which are cleaved from a larger precursor molecule. These forms vary in their potency and half-life, with G-17 being the most biologically active. Elevated gastrin levels can occur in conditions such as pernicious anemia, where gastric acid secretion is impaired, or in response to gastric bypass surgery, which alters normal digestive signaling.

Abnormal gastrin levels may contribute to gastrointestinal disorders. For example, excessive gastrin production can lead to hypersecretion of gastric acid, increasing the risk of peptic ulcers or Zollinger-Ellison syndrome, a rare condition characterized by gastrin-secreting tumors. Conversely, low gastrin levels may indicate atrophic gastritis or chronic atrophic gastritis, where stomach lining damage reduces acid production.

Diagnostic tests, such as serum gastrin measurements or gastric acid secretion tests, help evaluate gastrin-related disorders. Treatment often involves proton pump inhibitors to reduce acid production or surgical intervention in cases of tumors. Understanding gastrin’s role aids in managing digestive health and related complications.