entsyymieritys

Ensyymieritys is the biological process by which cells synthesize and release enzymes into ducts, lumens, or extracellular spaces. It is essential for digestion, defense, and tissue remodeling. Enzymes can be secreted in active form or as inactive precursors, called zymogens, that are activated at their site of action.

In humans, major enzyme secretions occur in the digestive system. The salivary glands release amylase to begin carbohydrate digestion in the mouth. The stomach secretes pepsinogen, which is activated to pepsin in acidic conditions. The pancreas releases pancreatic juice containing amylase, lipase, and proteases (as zymogens such as trypsinogen and chymotrypsinogen) into the small intestine. The intestinal brush border also presents enzymes that act at the mucosal surface.

The secretion of enzymes relies on specialized cellular pathways. Secretory cells, such as pancreatic acinar cells, package enzymes into secretory granules and release them by regulated exocytosis in response to meals. Ductal cells often modify the fluid and electrolyte content of secretions, such as adding bicarbonate. Activation of zymogens typically occurs in the intestinal lumen; for example, trypsinogen is activated by enterokinase to trypsin, which then activates other proteases.

Regulation is coordinated by hormones and nerves. Cholecystokinin (CCK) stimulates enzyme-rich pancreatic juice in response to fats and proteins, while secretin stimulates bicarbonate-rich fluid. Vagal stimulation also contributes to secretion during-or prior to meal ingestion.

Clinically, impaired enzyme secretion underlies exocrine pancreatic insufficiency and certain digestive disorders, necessitating enzyme replacement therapies and dietary adjustments.