Insulinlike Activity of Nonpancreatic Tumors Associated with Hypoglycemia

Abstract

Four non-islet-cell tumors associated with hypoglycemia have been extracted and assayed for insulinlike activity using rat hemidiaphragm. Extracts from 2 of them increased glucose uptake as well as glycogen deposition but did not contain insulin when assayed by an immunologic technique. The other 2 tumors, as well as a nonfunctioning islet cell tumor, had no such activity. When compared to the insulin content of functioning islet cell tumors, the activities in the 2 positive cases were quite low. Extraction of an islet cell carcinoma by both saline and acid alcohol indicated that much less activity is recovered by the former method. These results suggest that the hypoglycemia associated with some, but not all, tumors may be caused by the production of a substance with insulinlike activity.