TEMPORAL EXPRESSION OF THE GASTRIN (CCK-B) RECEPTOR DURING AZASERINE-INDUCED PANCREATIC CARCINOGENESIS

Cholecystokinin (CCK-A) and gastrin (CCK-B) receptors have been demonstrated in the azaserine-induced rat pancreatic carcinoma DSL-6. In order to determine at what stage in azaserine-induced pancreatic carcinogenesis gastrin (CCK-B) receptors are first expressed, we examined the binding of [I-125]gastrin-I to normal rat pancreas, azaserine-induced premalignant pancreatic nodules, grossly normal internodular pancreas, and DSL-6 carcinoma. We observed that specific gastrin binding was absent in normal pancreas, premalignant nodules, and internodular pancreas, and also reconfirmed our previous report of marked overexpression of gastrin (CCK-B) receptors in the DSL-6 carcinoma. Specific cholecystokinin (CCK) binding was present in all pancreatic tissue types tested. Therefore, we conclude that the presence of gastrin (CCK-B) receptors in the azaserine-induced pancreatic carcinoma DSL-6, in contrast to their absence in premalignant nodules, suggests that the expression of the gastrin (CCK-B) receptor may be important in the transformation from premalignant nodules to pancreatic cancer.