The effect of cholecystokinin (CCK) on [3H]phenylalanine and [14C]tyrosine incorporation into protein was studied in isolated rat pancreatic acini. CCK8, the biologically active octapeptide of CCK, had a biphasic effect on amino acid incorporation. The magnitude of the stimulatory effect (maximal at 10-10 to 3 x 10-10 M CCK8) was greater in diabetic rats, whereas the magnitude of the inhibitory effect (maximal at 10-8 M CCK8) was greater in normal rats. Omission of extracellular Ca2+ from the incubation media did not diminish the stimulatory action of CCK8. Addition of 10-4 M EGTA to media containing no added Ca2+ lowered basal incorporation, abolished CCK's stimulatory effect, and enhanced its inhibitory effect. Stimulation was restored in the presence of Ca2+. The stimulatory effect of the cholinergic analogue carbachol (10-5 M) on amino acid incorporation was also abolished by removal of extracellular Ca2+, whereas the stimulatory effect of insulin (1.67 x 10-8 M) remained intact. These findings suggest that CCK and other pancreatic secretagogues enhanced pancreatic protein synthesis via Ca2+, whereas stimulation by insulin occurs via another mechanism.
|Original language||English (US)|
|Journal||American Journal of Physiology - Gastrointestinal and Liver Physiology|
|State||Published - Jan 1 1982|
ASJC Scopus subject areas
- Physiology (medical)