AJP - Gastrointestinal and Liver Physiology, Vol 249, Issue 3 408-G415, Copyright © 1985 by American Physiological Society
Stimulation of pepsinogen secretion in permeable isolated gastric glands
S. H. Norris and S. J. Hersey
Rabbit isolated gastric glands were treated with digitonin so that
stimulation of pepsinogen secretion could be studied in a permeable system.
Criteria for permeabilization were the release of lactate dehydrogenase in
response to digitonin as well as the finding that calcium stimulation and
spermine inhibition required the presence of digitonin. Other evidence
confirmed that digitonin directly permeabilized chief cells. Pepsinogen
secretion was elicited from digitonin-treated gastric glands by a number of
agents, including calcium, vanadate, cholecystokinin octapeptide (CCK-OP),
8-bromo-adenosine 3',5'-cyclic monophosphate, and forskolin. Spermine was
found to inhibit secretion stimulated by each of these agents only in the
presence of digitonin, suggesting an intracellular site of spermine action.
We concluded that spermine inhibition of secretion could be used as a
marker of secretion elicited from permeable chief cells. The ability to
stimulate pepsinogen secretion by such agents as CCK-OP and forskolin
suggests that stimulus-secretion coupling is virtually intact even in
permeable chief cells. We felt that this preparation should offer unusual
opportunities for investigating the mechanisms involved in the
intracellular regulation and activation of pepsinogen secretion.
