Effect of "fractionated" insulins on total plasma insulin binding capacity and insulin requirements in severe diabetes.

Serial observations of insulin requirement and total plasma insulin binding capacity have been carried out on six xevere diabetics whose treatment was changed from standard soluble and isophane (NPH) insulins to "fractionated" preparations (Nordisk Insulin Ltd). No correlation was found between initial insulin dose and binding capacity, but changes in these two functions during the study period were closely correlated, both for the group as a whole and for individual patients in whom falls in insulin dose occurred. It is concluded that highly purified insulins could be valuable in the treatment of insulin-resistant cases, that their use is frequently associated with a gradual reduction in insulin dose, and that estimation of total plasma insulin binding capacity may indicate which patients are most likely to benefit from fractionated insulin. No sudden change in insulin requirement was seen on changing to purified insulin preparations.