AJP - Cell Physiology, Vol 248, Issue 3 235-C240, Copyright © 1985 by American Physiological Society
Influence of pH change on redox state and CCK-induced secretion in isolated perfused rat pancreas
N. Asada and T. Kanno
The isolated perfused rat pancreas was used to examine the influence of the
acid-base status of the perfusing solution on the redox states of
cytochromes and secretory responses. Lowering the pH in a perfusing
solution (pHe) from 7.3 to 6.8 induced simultaneous oxidation of
cytochromes aa3, b, and c + c1, and further lowering to 6.0 induced larger
oxidation of the cytochromes. Raising the pHe from 7.3 to 8.0 induced
reduction of the cytochromes. Continuous stimulation with synthetic
C-terminal octapeptide of cholecystokinin (CCK-8) at 100 pM induced the
maximum secretory responses (pancreatic juice flow, protein output, and
amylase output) during perfusion with the standard solution. The responses
were not inhibited at pHe 6.8 but were inhibited significantly at pHe 6.0
or 8.0. The responses induced by stimulation with 20 pM CCK-8 were
completely inhibited when pHe was lowered to 6.0 and CaCl2 was removed from
the perfusing solution.
