PEPSINOGEN 2, in Visit Clinic

Pepsinogen I (PGI) and II (PGII) are stomach zymogens that differ by origin and clinical use. PGI is produced mainly by chief and mucous neck cells in the gastric fundus/corpus; PGII is made in fundic and antral mucosa plus pylorus, duodenum and Brunner’s glands. Serum PGI falls in corpus atrophy, PGII less so; the PGI/PGII ratio helps screen for gastric atrophy.

Pepsinogen II is an inactive precursor (zymogen) of the digestive enzyme pepsin, secreted by gastric mucosal cells (including chief and mucous neck cells) and by pyloric/duodenal glands. Stomach acid converts it to active pepsin for protein digestion. Serum pepsinogen II and the pepsinogen I/II ratio are clinical biomarkers: levels rise with gastric inflammation and Helicobacter pylori infection and help detect atrophic gastritis.

Pepsinogen 1 is an inactive precursor produced by gastric chief cells in the stomach body and fundus. In acidic gastric juice it converts to active pepsin, initiating protein digestion by cleaving dietary proteins into smaller peptides. Its secretion supports efficient gastric proteolysis; circulating pepsinogen I levels are also used clinically as a marker of gastric mucosal function.

Elevated pepsinogen levels generally indicate increased gastric mucosal activity or inflammation. Causes include acute or chronic gastritis, peptic ulcer disease, H. pylori infection, and gastroesophageal reflux. High pepsinogen II often reflects Helicobacter-related inflammation, whereas isolated high pepsinogen I suggests increased acid-secreting mucosa. Interpretation requires clinical correlation and further testing to identify the cause.

Gastritis is inflammation of the stomach lining and has many causes—most commonly Helicobacter pylori infection, NSAIDs, alcohol or stress. A specific form, autoimmune (type A) gastritis, exists: the immune system attacks parietal cells and intrinsic factor, causing chronic atrophic gastritis and risk of pernicious anemia. Autoimmune gastritis is less common than other causes.

There are two main pepsinogen types: pepsinogen I (PG I or pepsinogen A) and pepsinogen II (PG II or pepsinogen C). PG I is produced mainly by chief cells in the gastric fundus and corpus; PG II is secreted by chief and mucous cells in the fundus, antrum, pylorus and proximal duodenum. Serum levels and the PG I/II ratio help assess gastric mucosal health.