Enterokinase (also called enteropeptidase) is an enzyme produced by duodenal epithelial cells that cleaves inactive pancreatic zymogen trypsinogen into its active form, trypsin. Trypsin in its active form is involved in breakdown of dietary amino acids and cleavage of other dietary proteases.
There are two forms of amylase, pancreatic amylase and salivary amylase. Salivary amylase breaks down starch to disaccharides. Pancreatic amylase breaks down starch to oligosaccharides and disaccharides. Lipase is a secreted pancreatic enzyme that breaks down fats.
Whitcomb states that the pathogenesis of acute pancreatitis is due to inappropriate activation of trypsinogen to trypsin. Active trypsin cleaves and activates other pancreatic zymogens leading to pancreatic injury and disproportionate inflammatory response.
Carroll et al. provides a discussion regarding how trypsinogens and pancreatic proteases are involved in the autodigestive processes of acute pancreatitis. Table 2 (included as an image below) from this reference lists some of the biological markers used to predict the severity and prognosis of the disease. The most common markers of acute pancreatitis are plasma amylase and lipase (which are secreted by the acinar cells of the pancreas), with plasma lipase as a more sensitive readout that plasma amylase. Other potential biomarkers include trypsinogens and pancreatic proteases (involved in the aforementioned autodigestive processes).
Illustration A shows how trypsinogen is released into the lumen of the small intestine, then converted into its active form in order to digest proteins. Trypsinogen is activated by the enzyme enterokinase, which is embedded in the intestinal mucosa. Illustration B shows the different serum markers that are currently being used for determining the diagnosis and prognosis of acute pancreatitis.
Answer 1: Amylase degrades complex carbohydrates into mono-, di-, and oligosaccharides.
Answer 2: Lipase is necessary for triglyceride breakdown into monoglycerides and fatty acids.
Answer 3: Cholecystokinin stimulates bile secretion by the gallbladder in response to a fatty meal.
Answer 5: Secretin is released by the S cells of the duodenum, and regulates the pH of duodenal contents. It functions to increase pancreatic bicarbonate secretion and decrease gastric acid secretion. By decreasing gastric acid secretion and increasing bicarbonate production, it neutralize the gastric acid in the duodenum and hence allows the pancreatic enzymes to function (if not, the acidic environment can cause the pancreatic enzymes to degrade).
Whitcomb DC. Clinical practice. Acute pancreatitis. N Engl J Med. 2006 May 18;354(20):2142-50. Review. PubMed PMID: 16707751.
PMID:16707751 (Link to Abstract)
Carroll JK,Herrick B, Gipson T, Lee SP. Acute Pancreatitis. Am Fam Physician. 2007 May 15;75(10):1513-20
PMID:17555143 (Link to Abstract)