Effects of in vivo administration of pentagastrin, secretin, and 13-Nle-Motilin on the in vitro incorporation of 14C-leucine into protein of human gastric mucosa.

Under endoscopic control, biopsy specimens were taken from the oxyntic gland area of the stomach before and after administration of pentagastrin, synthetic secretin, and 13-norleucine motilin (13-nle-motilin), respectively. In 29 volunteers, the basal rate of 14C-leucine incorporation into mucosal protein averaged 41.2 +/- 7.7 X 103 cpm/mg protein (mean +/- S.D.). One and 4 hours after s.c. administration of pentagastrin (6 mug/kg body weight), values were significantly increased (p less than 0.05) by 18.9 and 21.8%, respectively, with respect to the basal level. One hour after an intravenous shot of 2 CU per kg body weight of secretin, gastric mucosal protein synthetis was not substantially inhibited, whereas a 1-hour continuous i.v. infusion of 13-nle-motilin (0.4 mug/kg body weight, hr) significantly decreased 14C-leucine incorporation rates by 17.5% (p less than 0.05). In contrast to rats, 1 hour after s.c. pentagastrin, protein synthesis in human duodenal mucosa was not altered. From these results it may be concluded that pentagastrin has a trophic influence on gastric mucosa in man. Moreover, the data presented are compatible with the hypothesis that gastrin and motilin may be involved in the regulation of human gastric mucosal protein synthesis.