Effect of truncal vagotomy and pylorotomy on gastric emptying

The effect of transthoracic vagotomy and a conventional pylorotomy on gastric emptying of a hyperosmolar glucose meal was evaluated in four dogs by means of an isotope technique. The measurements were made preoperatively and 1 month and 3-6 months after each operation. Vagotomy significantly increased the initial rate of gastric emptying, whereas the total fraction of the meal emptied in 60 min was the same as before operation. The pylorotomy did not alter the emptying. Approximately 50% of the meal was still retained in the stomach at the end of the tests. The abnormal gastric emptying of the glucose meal after vagotomy was normalized by drinking an 'aperitif' of 20% soya bean oil 15 min before the ingestion of the glucose meal. It is concluded that a vagotomy alters the pattern but not the 60-min fraction of gastric emptying of a liquid meal, whereas a pylorotomy alters neither the pattern nor the 60-min fraction of gastric emptying. The vagally denervated gastrointestinal tract has maintained mechanisms for control of the gastric emptying.