Site of origin of the hormone responsible for gastric hypersecretion associated with portacaval shunt.

Previous studies in our laboratory established that the intestinal phase of gastric secretion and the acid hypersecretion associated with portacaval shunt are mediated by a potent hormone in both dogs and humans. The present investigation was designed to localize the site of origin of the intestinal phase hormone by measuring the 5 1/2 hour gastric secretory response to the instillation of a standard meal into isolated segments of jejunum, ileum and colon before and after portacaval shunt. Twenty-four dogs with Thirty-Villa fistulas and Heidenhain pouches underwent 48 intestinal meal tests prior to portacaval anastomosis, and 46 tests following shunt. Instillation of food into the isolated jejunum produced substantial gastric secretion before portacaval shunt, and sustained and highly significant acid hypersecretion after shunt (p = < 0.001). The magnitude of the hypersecretion averaged over six times the basal rate of acid production. Food in the isolated ileum stimulated modest gastric secretion in unshunted dogs, but portacaval shunt failed to enhance acid output. Food in the colon did not stimulate gastric acid production in either unshunted or shunted dogs. It is concluded that the jejunum is the major source of the hormone responsible for the intestinal phase of gastric secretion and for the profound acid hypersecretion associated with portacaval shunt.