Abstract
A model for spontaneous tumour formation in the rat pancreas is described that requires neither cocarcinogens nor dietary manipulation. Short term hypercholecystokininaemia, when induced by raw soya flour feeding, induces benign and malignant tumours of the rat pancreas. Pancreaticobiliary diversion (PBD) results in hypercholecystokininaemia and in the short term, pancreatic hyperplasia. Longterm PBD was done to establish whether hypercholecystokininaemia thus produced would also lead to pancreatic neoplasia. After a period of 16-21 months hyperplastic and adenomatous nodules, one of the latter showing carcinoma in situ, were found in PBD rats but not in sham operated control rats.