Prostacyclin: a potent activator of human colonic adenylate cyclase activity.

Prostacyclin and its stable catabolite 6-keto-prostaglandin F1 alpha were tested on the human colonic mucosal adenylate cyclase which represents the key enzyme in the secretory process in this organ. Prostacyclin was able to activate dose-dependently the human cyclase system. Saturating concentrations of prostacyclin and 6-keto-prostaglandin F1 alpha (each 0.28 mM) increased the enzyme activity 2.5-fold and only 1.4-fold, respectively. The presence of prostacyclin receptor sites in human colonic mucosa suggests a physiological role of this novel prostaglandin in human colonic function.