Cholinergic release of gastrin by feeding in cats

The effect of atropine on acid secretion and serum gastrin level after feeding was studied in 8 cats with denervated fundic pouches (Heidenhain pouch, HP). Serum gastrin concentration was measured by radioimmunoassay. In the control experiments, the mean peak acid response occurred 45 min after feeding and the mean peak gastrin concentration 15 min after feeding. After the 1st postprandial hr, acid secretion declined but the gastrin level remained elevated. Atropine, 0.1 mg per kg intravenously 5 min before feeding, depressed both acid secretion and the increase in serum gastrin concentration during the 1st postprandial hr. In both the control and atropine experiments, acid secretion and serum gastrin level were correlated significantly during the 1st postprandial hr, but no correlation was found later in the experiments. The reduction by atropine of the acid and serum gastrin responses varied among the cats but were correlated significantly. It is concluded that a cholinergic mechanism is implicated in the release of gastrin by feeding in cats during the 1st postprandial hr. Atropine reduces the HP acid response to feeding at least in part by depressing the release of gastrin.