AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 4 398-G404, Copyright © 1986 by American Physiological Society
Secretion of pyruvate and lactate in pancreatic juice induced by acetazolamide or secretin
T. Kuroshima, S. Himeno, M. Kurokawa, K. Tsuji and S. Tarui
In vivo studies using pentobarbital sodium-anesthesized dogs were performed
to investigate whether a transport pathway for pyruvate and lactate is
present in the exocrine pancreas. Concentrations of both acids were
measured in peripheral blood and pancreatic juice before and after
intravenous 15-min administration of 2.25 mmol/kg DL-lactate, superimposed
on continuous intravenous infusion of 3 U X kg-1 X h-1 secretin. The
concentration ratio of lactate to pyruvate in pancreatic juice was found to
be approximately 1, a lower value than found in other tissues or body
fluids. D-lactate, not detected in either blood or juice during basal
periods, rapidly appeared in both fluids in parallel with the physiological
isomer L-lactate, after the infusion of DL-lactate. Further addition of
acetazolamide or a high dose of secretin caused a marked secretory response
of pyruvate and lactate with no increase in juice bicarbonate levels. We
conclude that these acids can be transported from blood to lumen when the
transmembrane pH gradient across the duct cell membranes is augmented by
stimulants via a proton pump mechanism involving a CO2-HCO3-buffer system.
