The effect of vagotomy on the canine enterogastrone mechanism.

The effect of truncal vagotomy on the enterogastrone mechanism was evaluated in dogs with Heidenhain pouches and gastric and pancreatic fistulas. During continuous infusion of pentagastrin, 8 microg-Kg.-hr., HCl was infused into the duodenum in doses of 12, 18, and 24 mEq. per hour before and one month following transthoracic vagotomy. The effect of vagotomy on the inhibition of pentagastrin-stimulated Heidenhain pouch hydrogen ion output produced by the endogenous release of duodenal hormones was evaluated. The results indicate that there was no difference in the degree of inhibition produced by 12 and 18 mEq. intraduodenal HCl before and after vagotomy. When 24 mEq. per hour HCl was infused, the percent inhibition was significantly greater after vagotomy compared to values before vagotomy. The D50 of intraduodenal acid for inhibition of Heidenhain pouch hydrogen ion output was not altered by vagotomy, whereas the calculated maximal response (inhibition) was increased after vagotomy. Pancreatic volume was greater after vagotomy when compared to values before vagotomy, when 24 mEq. of HCl per hour was infused into the duodenum. These data suggest that vagotomy does not impair the effectiveness of the enterogastrone mechanism and at high doses of intraduodenal acid may augment it.