AJP - Gastrointestinal and Liver Physiology, Vol 253, Issue 1 62-G67, Copyright © 1987 by American Physiological Society
Potential mediation of somatostatin secretion from canine fundic D-cells by protein kinase c
T. Chiba, K. Sugano, J. Park and T. Yamada
We examined the possible importance of protein kinase c-dependent
mechanisms in mediating the stimulatory effects of gastrin and
cholecystokinin (CCK) on the release of somatostatin-like immunoreactivity
(SLI) from isolated canine fundic D-cells. Diacylglycerides, presumably the
products of phosphoinositide breakdown that activate protein kinase c, and
phospholipase C, which catalyzes the production of endogenous
diacylglycerides from membrane phospholipids, both stimulated SLI secretion
in a dose-dependent fashion. Both classes of agents potentiated the actions
of adenosine 3',5'-cyclic monophosphate-dependent agonists but not those of
gastrin and CCK. The stimulatory effects of gastrin and CCK correlated with
their abilities to enhance the incorporation of 32P into membrane
phosphatidyl inositol and phosphatidic acid and promote the release of
[3H]inositol trisphosphate from prelabeled D-cells, two parameters of
phosphoinositide turnover. These data suggest that protein kinase c may
serve to transduce the signals activated by gastrin and CCK in D-cells.
