Insulin and Proinsulin Content of Pancreases from Diabetic and Nondiabetic Subjects

The content of immunoreactive insulin (IRI) extractable with acid ethanol from the head, body and tail of the pancreas was. studied in thirty-two nondiabetics, eleven maturity-onset diabetics and four juvenile diabetics. In nondiabetics IRI content ranged from 0.1 to 4.8 U. per gram wet pancreas. The tail had the highest insulin content, but the body of the pancreas could be taken to represent the entire pancreas. The insulin content of pancreases from eleven maturity-onset diabetics ranged from 0.1 to 6.5 U. per gram wet pancreas. It showed a progressive decline with the duration of diabetes. The IRI content of pancreases from four juvenile diabetics was low. The proportion of proinsulinlike component, estimated by gel filtration in the pancreatic extracts, ranged from 0.2 to 5 per cent of the insulin peak and was not different in diabetics.