Comparison of Prostaglandin E 1 and Norepinephrine on the Gastric Mucosal Circulation

Abstract

Summary

Secretion, mucosal blood flow, and the ratio (R) of blood flow to secretory rate were measured in conscious dogs provided with a gastric fistula. Secretion was stimulated to steady rates about one third of maximal with either pentagastrin or histamine. Prostaglandin E₁ (PGE₁) or norepinephrine was administered in doses of 0.1 or 1.0 μg kg^-1 min^-1. With the high dose of either agent, secretion was decreased, whether stimulated by histamine or pentagastrin, but the ratio of blood flow to secretory rate was decreased only with norepinephrine. It is concluded that norepinephrine operates to reduce secretion by limiting mucosal blood flow. On the other hand, PGE₁, which is a powerful vasodilator, reduces secretion by a primary mechanism other than restricting gastric mucosal blood flow. The decrease in blood flow seen with PGE₁ appears to be the result and not the cause of gastric secretory inhibition.

I am indebted to Drs. Morton I. Grossman and Andre Robert for their critical comments and suggestions, to Dr. John McCoy of the Southwest Research Support Center for statistical and computational assistance, and to Mr. Alvin C. K. Chang and Mrs. Tulin Oruc for technical support. These investigations were supported by a grant from the U. S. Public Health Service (N.I.H., AM 11073-04). The PGE₁ used in this study was supplied by Dr. John Pike (Upjohn).