Human pepsinogens I (PGI) and II (PGII) are proenzymes of pepsin—an endoproteinase of gastric juice. PGI is secreted mainly by chief cells in the fundic mucosa , whereas PGII is also secreted by the pyloric glands and the proximal duodenal mucosa . Helicobacter pylori-related gastric atrophy and further changes tend to start at the antrum and antrum-corpus junction and the antral lesser curvature and incisura, and progress proximally in the distal corpus and, finally, the proximal corpus. In this way, serum PGI and PGII concentrations and the ratio between PGI and PGII may be related to the histologic and functional status of the gastric mucosa .