PGI2-sensitive human adenylate cyclase in biopsy specimens of corpus, antral and duodenal mucosa.

The distribution of prostacyclin-(PGI2-)sensitive cyclase in human gastric and duodenal mucosa was studied. Like PGE2, PGI2 induced a dose-dependent increase of enzyme activity throughout the stomach and the duodenum. Maximal effects (about 2.5- to 3.0-fold increase) were observed at a PGI2 concentration of 0.28 mmol/l. The stable breakdown product 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) was much less active. The equal distribution of the PGI2-sensitive adenylate cyclase in the human upper alimentary tract suggests a localization of this enzyme system in cells not directly related to gastric acid secretion.