<prompt> Answer this question truthfullyWhat is the underlying mechanism or physiology behind Zollinger-Ellison syndrome?  <response>: <reason> Multiple endocrine neoplasia type 1 MEN 1 Gastrinoma duodenal gastrinoma and pancreatic gastrinomas Usually these gastriomas are small less 1 cm, multiple ones,less often to metastasize to liver rather than pancreatic gastrinomas. Peptic ulcer disease 