The State of Pancreatic and Serum Insulin: Results of Immunoassay

Insulin fractionation of human and canine pancreata and sera has been studied by immunoassay. Several procedures designed to separate bound and free insulin have been utilized. Immunoassay has demonstrated pancreatic insulin to have a very low solubility in saline. However, a cation-bound fraction could not be demonstrated in either the pancreas or serum. These results suggest that cation-bound insulin-like activity demonstrated by rat diaphragm or adipose tissue assay does not represent pancreatic insulin.