Prostaglandin action on pancreatic blood flow and on electrolyte and enzyme secretion by exocrine pancreas in vivo and in vitro

Abstract

SUMMARY1. Intra-arterial injection or infusion of prostaglandins E1 and E2 into anaesthetized cats caused a fall in arterial blood pressure, a reduction in pancreatic blood flow and an inhibition of secretin-stimulated pancreatic electrolyte secretion. In some experiments these effects were preceded by a transient increase in blood flow and secretion.2. The fall in blood pressure and reduction in blood flow, but not the inhibition of secretion, were much less marked following administration of the a-adrenergic blocking agent phenoxybenzamine. This stimulatory action was markedly potentiated by theophylline. 5. Enzyme secretion was not stimulated by any of the prostaglandins, even in the presence of theophylline.6. It is concluded that prostaglandins can stimulate electrolyte transport by exocrine pancreas, perhaps through a mechanism involving adenylate cyclase, but that in vivo this action is masked by a secondary inhibition resulting either from vasoconstriction, or from the vibration of an antisecretory agent, or both.

Comparison of Natural and Synthetic Prostaglandins on Gastric and Pancreatic Secretions and Peptic Ulcer Formation in Conscious Cats

“…In in vivo experiments performed in anes thetized cats, PGs of the F series were found by these authors (7) to cause an inhibition of pancreatic electrolyte secretion. The reason for the discrepancy between our study and other studies is not apparent, but it can probably be explained in part by the methods employed to examine pancreatic secretion and the use of relatively high doses of PGs causing many severe side-effects as indi cated by the massive autonomic discharge (26) and probably resulting in vasoconstriction or liberation of antisecretory agents or both (7).…”

The Relationship Between Glucagon and Prostaglandin F in Stimulating Canine Hepatic Bile Flow

“…The prostaglandins have been identified as altering exocrine function throughout the gastrointestinal tract (34)(35)(36) responses which may be due to prostaglandin-produced changes in hormone release.…”

Duodenal Mucosal Bicarbonate Secretion in Pigs Is Accompanied by Compensatory Changes in Pancreatic and Biliary HCO3-Secretion

“…To date, there have been no reports illustrating the effect of intraduodenal infusion of the synthetic PGEl analogue misoprostol on pancreatic or hepatic bicarbonate secretion in response to exogenous secretin. The effect of natural PGEl has been studied in several previous studies, but results are conflicting, showing inhibition in some studies and no effect in others, depending on dosage, method of administration, and species studied (19)(20)(21)(22)(23)(24)(25). If prostaglandins do in fact inhibit pancreatic secretion, indomethacin could theoretically influence pancreatic secretion directly by removal of the inhibitory effect of locally generated prostaglandins, thus explaining the observed increase in pancreatic bicarbonate secretion in response to intraduodenal HC1.…”