[Serum insulin binding activity and diabetic retinopathy]

Radiochemical evaluation of serum insulin-binding activity in diabetics shows that there are no correlations between this behaviour and diabetic retinopathy. High values are mainly encountered in insulin-dependent diabetics; its nil or poor inhibition, owing to the effect of preincubation of the serum with high concentrations of unlabelled insulinic antigen, suggests that the phenomenon is connected above all to the presence of aspecific serous factors that "bind" the labelled hormone.