Pancreatic cancer develops at approximately 25 weeks after 6 weeks of weekly subcutaneous administration of N-nitrosobis (2-oxypropyl)amine in the Syrian golden hamster. We studied the glucose tolerance and insulin secretion during the development of pancreatic cancer in this model. Every 6th week after start of treatment, glucose was infused intravenously for 30 min (10 mg/min). It was found that the glucose tolerance and glucose-stimulated insulin secretion were normal at 6, 12, and 18 weeks after start of treatment compared with age-matched saline-injected controls. By contrast, after 24, 30, and 42 weeks an exaggerated plasma-glucose response and a concomitant impaired plasma-insulin response occurred during the glucose infusion (P < 0.05). We therefore conclude that the development of pancreatic cancer in this model is accompanied by glucose intolerance and impaired insulin secretion, and that these effects occur concomitantly with the development of cancer.