Eisenberg Mm

Prostaglandin Inhibition of Innervated Antral Motility in Dogs

Summary PGE1 has been analyzed in terms of its effect on vagally driven gastric motor activity in dogs; profound inhibition of 2-deoxy-d-glucose stimulated motility was observed. The effect of PGE1 on serum calcium, potassium, and blood sugar levels has been monitored; no significant change in calcium or potassium during PGE1 infusion has been noted. Blood sugar, traditionally elevated by 2-deoxy- d-glucose, was not altered from its usual pattern after PGE1 infusion. PGE1 is capable, in doses previously shown to have an inhibitory effect on gastric secretion, to inhibit gastric motility as well. The precise mode of action is speculated upon but remains undisclosed. A special thanks is given to Miss Catherine Holm for her technical assistance and to Upjohn Company for the PGE1.

The effect of small bowel bypass and subsequent resection on gastric acid secretion and serum gastrin

Evaluation of gastric acid secretion and serum gastrin response to proximal or distal intestinal bypass and subsequent resection was undertaken. Ten dogs with gastric fistulas underwent control secretory studies consisting of basal acid output (BAO), maximal vagal stimulation (2 deoxy-d-glucose (2DG) 150 mg/kg iv), maximal histamine stimulation (160 μg/kg/hr iv), and test meal stimuli. Serum gastrin was measured basally and following gastric stimulation. Dogs were then divided into two bypass groups: Group I, distal bypass, leaving 40 cm jejunum and 4 cm ileum; and Group II, proximal bypass, leaving 4 cm jejunum and 40 cm ileum. Postoperatively, repeat studies were performed. Both groups then underwent resection of the bypassed segments followed by repeat secretory and gastrin tests. BAO was significantly increased in Group I dogs. BAO increased from a control of 0.04 ± 0.02 to 0.51 ± 0.19 meq H+/60 min (±SEM). No significant changes in BAO were observed in Group II following bypass. Acid secretion to maximal vagal or maximal histamine stimulation was not significantly different in either group. Serum gastrin response was unchanged in either group following a test meal. In Group I dogs, resection of the previously bypassed bowel produced a further significant increase in BAO (1.44 ± 0.4 meq H+/60 min). After resection of the bypassed bowel, there was no significant change in basal or stimulated gastrin. Gastric fistula BAO increased following 90% distal but not proximal bypass; subsequent resection of the bypassed segment produced a further increase in BAO. Acid secretory responses to both histamine and 2DG were not influenced by either bypass or resection. An increase in BAO without a change in the background of serum gastrin may suggest the presence of a gastric secretory inhibitor in the distal small bowel.

The relationship of lumenal pH and distention to antral G-cell numbers☆

Abstract This study was designed to study the importance of lumenal pH and antral distention on G-cell numbers. Antrocolic transpositions (ACT) were performed in female Sprague-Dawley rats, orienting the peristalsis of the transposed antra to result in either filling or emptying. In some animals a segment of parietal cell bearing corpus mucosa was left with the antrum to provide a relatively acid lumen. Sham operations were performed in controls. The rats were sacrificed after 15 days. The self-filling antra were grossly distended compared with the self emptying antra. G cells were quantitated by means of a double-antibody immunofluorescence technique. All ACT rats had significantly increased G-cell numbers and serum gastrin levels compared with controls. The magnitude of the increase depended on the presence or absence of distention and an acid environment. The most marked hyperplasia occurred in the group with distended antra and no acid. The group with self-filling antra but an acid lumen showed a significant but lesser increase. The least degree of hyperplasia was observed in the group with self-emptying antra and an acid lumen. These data indicate that both distention and a nonacid lumenal pH encourage G-cell hyperplasia. The nonacid lumen is a more potent stimulus than distention but the two are synergistic.