In eleven insulin sensitive and in six insulin resistant diabetic patients, insulin-like activity was measured in unmodified serum and in the corresponding acid ethanol extract shown to be free of insulin antibodies. Whereas most of the insulin responsive and four insulin resistant diabetic patients exhibited a similar ratio of insulin-like activity of serum to the respective serum extract, two patients with insulin resistance exhibited a more than one-hundredfold increase in this ratio.
Of the factors analyzed, i.e., length of insulin treatment, daily insulin dose, maximum serum insulin binding capacity, serum ILA and serum extract ILA, only insulin binding capacity and serum extract ILA exhibited a positive correlation in both the insulin responsive and insulin resistant patients.