AJP - Gastrointestinal and Liver Physiology, Vol 244, Issue 2 192-G197, Copyright © 1983 by American Physiological Society
Stimulation of pepsinogen release from isolated gastric glands by cholecystokininlike peptides
S. J. Hersey, D. May and D. Schyberg
Gastric glands isolated from rabbit stomach were employed to study the
regulation of pepsinogen secretion by peptide hormones. Cholecystokinin
octapeptide (CCK-OP) stimulated pepsinogen secretion with an ED50 of about
1 nM. Caerulein was as effective as CCK-OP but less potent (ED50, 10 nM).
Gastrin (HG-17) was found to be a weak stimulus, being only about 20% as
effective as CCK-OP or caerulein. Sulfation of CCK-OP and caerulein was
found to be important for potency but did not alter efficacy. Peptide
stimulation of pepsinogen secretion was unaffected by cimetidine, atropine,
or propranolol. Combinations of peptides resulted in less-than-additive
responses, as did the combination of peptides with carbachol. In contrast,
combination of peptides with isoproterenol resulted in additive responses.
Accumulation of the weak base aminopyrine was used to measure acid
formation by the gastric glands. The peptides gastrin, CCK-OP, and
caerulein were found to be equally effective in stimulating acid formation.
The peptide stimulation of pepsinogen secretion was inhibited by dibutyryl
cGMP, whereas stimulation of acid formation was not inhibited by the cyclic
nucleotide. The results indicate that gastric glands contain at least two
peptide receptors distinguishable by sensitivity to dibutyryl cGMP. The
peptide receptor associated with pepsinogen secretion appears to be
selective for CCK relative to gastrin.
