AJP - Gastrointestinal and Liver Physiology, Vol 254, Issue 1 25-G32, Copyright © 1988 by American Physiological Society
Distinct activation of Na+-H+ exchange by gastrin and CCK peptide in acini from guinea pig
M. J. Bastie, M. Delvaux, M. Dufresne, J. S. Saunier-Blache, N. Vaysse and A. Ribet
Institut National de la Sante et de la Recherche Medicale U 151, CHU Rangueil L3, Toulouse, France.
The effect of cholecystokinin (CCK)-gastrin family peptides (caerulein,
unsulfated gastrin-17, and pentagastrin) and secretin in activating
amiloride-sensitive 22Na uptake were investigated in guinea pig pancreatic
acini. Secretin had no effect, but CCK-gastrin peptides stimulated the
amiloride-sensitive 22Na uptake. The effect of caerulein was inhibited by
dibutyryl guanosine 3',5'-cyclic monophosphate (cGMP) and asperlicin,
indicating that activation of the Na+-H+ antiport caused by caerulein is
mediated by CCK receptors. The effect of gastrin was dibutyryl cGMP and
asperlicin insensitive, whereas the effect of pentagastrin was inhibited by
the CCK antagonists but with a low affinity, indicating that the effect of
gastrin and that of pentagastrin was CCK receptor independent. The calcium
ionophore A23187 caused an increase in amiloride-sensitive 22Na uptake.
However, the effect of caerulein, which increased internal calcium
concentration, was not modified after depletion of intracellular calcium,
and that of CCK-gastrin family peptides was not dependent on external
calcium concentration. Activation of amiloride-sensitive 22Na uptake was
also induced by 12-O-tetradecanoylphorbol 13-acetate and
1-oleoyl-2-acetyl-glycerol. Activation of protein kinase c may be involved
in the mechanism of caerulein or gastrin in activating the Na+-H+ exchange.
