Histological localization of plasminogen activator and proteolytic activity in the human stomach and duodenum.

Plasminogen activator activity has been localized in gastric and duodenal tissue using a histological technique. This activity could be separated from proteolytic activity by incorporating in-aminocaproic acid into the fibrin substrate or by heat treatment. Plasminogen activator activity was found in relation to mucosal and submucosal blood vessels in the tissues studied. Proteolytic activity was identified in the surface epithelium, the gastric antral and fundal glands, and in the antral submucosal fat. Proximal duodenal tissue contained proteolytic activity in relation to Brunner's glands.