Exocrine pancreatic secretion, digestive enzymes and tests of pancreatic function
How acinar and duct cells make pancreatic juice, the phases of secretion, why enzymes are made as zymogens, how CFTR sets bicarbonate output, and how to read amylase, lipase, faecal elastase and faecal fat, with worked numbers for fat absorption and enzyme replacement dosing.
Tier 1Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Acinar cells make enzymes (protein-rich, low-volume). Duct cells make bicarbonate and water through CFTR. CCK and vagal acetylcholine drive acinar output; secretin drives duct output.
- Proteases and phospholipase are secreted as inactive zymogens and activated in the duodenum by enteropeptidase. Premature activation inside the gland is the first step in pancreatitis.
- The pancreas has a large reserve. Steatorrhoea appears only after about 90% loss of lipase output.
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Sources
- Sleisenger and Fordtran's Gastrointestinal and Liver Disease (11th ed.)Elsevier (Feldman, Friedman, Brandt, 2021), 2021
- Smith RC et al. Summary and recommendations from the Australasian guidelines for the management of pancreatic exocrine insufficiency. Pancreatology 2016;16(2):164-80AU/NZPancreatology (Elsevier), for the Australasian Pancreatic Club, 2016
- Nikfarjam M, Wilson JS, Smith RC. Diagnosis and management of pancreatic exocrine insufficiency. Med J Aust 2017;207(4):161-5AU/NZMedical Journal of Australia, 2017
- Whitcomb DC et al. AGA Clinical Practice Update on the Epidemiology, Evaluation, and Management of Exocrine Pancreatic Insufficiency: Expert Review. Gastroenterology 2023;165(5):1292-301American Gastroenterological Association, 2023
- Last updated
- 14 November 2026
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