Identification of Insulin and Glugacon in a Bronchogenic Metastasis1

Abstract

By means of highly specific radioimmunochemical techniques, acid-alcohol extracts of a hepatic metastasis from an undifferentiated bronchogenic carcinoma were found to contain remarkably high concentrations of both insulin and glucagon. Insulin concentration was at least 0.26 U/g and glucagon concentration 0.53 [mu]g/g of wet tumor weight. At these levels it is possible that 260 U of insulin and 0.5 mg of glucagon were present in the hepatic metastases alone. Surrounding liver tissue had much lesser concentration of both. For purposes of further identification of the tumor "hormones", their electrophoretic characteristics and their response to cysteine and trypsin incubation were examined, and the insulin-like activity (rat diaphragm method) in the extract was determined. The results failed to provide evidence that the tumor "hormones" differ from their pancreatic counterparts in any of these respects, and support the immunologic identification as insulin and glucagon. Specific immunochemical techniques, supported by tests of physicochemical and biologic characteristics, reveal the presence of 2 insular hormones in a tumor of nonendocrine origin. Although there was no known endocrine abnormality in this patient, possible implications of these findings in respect to the various clinical syndromes of hormones excess in nonendocrine malignancies are discussed.