AJP - Gastrointestinal and Liver Physiology, Vol 241, Issue 5 359-G364, Copyright © 1981 by American Physiological Society
Effect of extracellular manganese on amylase release from dispersed pancreatic acini
S. Abdelmoumene and J. D. Gardner
In dispersed acini from guinea pig pancreas, adding extracellular manganese
increased amylase release. A significant effect could be detected with 0.25
mM manganese, and maximal stimulation occurred with 1 mM manganese. When
manganese was added, the rate of amylase release did not change during the
first 20 min of incubation and then gradually increased to a new steady
state by 80 min, which with 1 mM manganese represented a fourfold increase
in the rate of enzyme release. Extracellular manganese inhibited the
stimulation of amylase release caused by those secretagogues that mobilize
cellular calcium but augmented the stimulation caused by those
secretagogues whose actions are mediated by cellular cAMP. The mechanism by
which manganese altered stimulated amylase secretion differed from the
mechanism by which manganese stimulated basal amylase release because the
change in stimulated release was maximal within 10 min, whereas the change
in basal release did not occur until after 20 min. The actions of manganese
on secretagogue-stimulated amylase release were not attributable to
manganese-induced changes in secretagogue-stimulated calcium outflux or
cAMP and, instead, appear to result from actions of manganese on one of the
later steps in the mechanisms for stimulating the secretory process.
