Gastric chief cell
Exocrinocytus principalis
Also known as: chief cell, zymogenic cell, peptic cell
Chief cells are basophilic, protein-secreting cells at the base of the oxyntic glands. They release pepsinogen and gastric lipase.
Overview
Chief cells have the features of a typical protein-exporting cell: abundant rough ER, which makes the basal cytoplasm basophilic, a prominent Golgi apparatus, and apical zymogen granules.
They secrete pepsinogens (I and II). In acid below about pH 5 these are cleaved to active pepsin, which then activates more pepsinogen (autocatalysis). Pepsin works best at about pH 2. It is an endopeptidase that prefers bonds next to aromatic and leucine residues. It carries out about 10–20% of protein digestion and is especially good at digesting collagen. It is irreversibly inactivated in the neutral to alkaline duodenum.
Chief cells also secrete gastric lipase, an acid-stable lipase that hydrolyses a minor but useful share of dietary triglyceride. It matters most in infants and in pancreatic insufficiency.
Anatomy
- Histology
Cuboidal or low columnar cells with basal basophilia and apical eosinophilic granules, clustered at the gland base.
Function
- Secrete pepsinogen, which starts protein digestion.
- Secrete gastric lipase, which starts triglyceride digestion.
- Secretions
Pepsinogen I and II and gastric lipase.
- Regulation
Stimulated mainly by vagal ACh, and also by gastrin, secretin and local acid-triggered enteric reflexes. Pepsinogen secretion therefore tends to run in parallel with acid secretion.
Clinical significance
Serum pepsinogen as a biomarker
A low pepsinogen I level, or a low pepsinogen I:II ratio, indicates atrophic gastritis of the body. It is used in some countries to screen for people at high risk of gastric cancer.
Compiled from standard anatomy and physiology references — see the Digestive System sources. For education only; not medical advice.