Abstract
A method for the determination of free, active insulin in the sera of the insulin-treated diabetics by radioimmunoassay with previous precipitation of anti-insulin antibody by polyethylene glycol treatment was described.
The recovery test with cold insulin showed eighty-nine per cent of recovery of free insulin and no recovery of antibody-bound insulin.
The fasting free insulin levels of the patients were slightly lower as compared to that of normal persons except some patients with infections and liver diseases and showed no correlation to the antibody titer, total insulin levels, insulin requirement and term of insulin treatment.
The negligible increase of free insulin levels was observed in the course of glucose tolerance test of the insulin-treated patients but a marled increase of free insulin followed by a exaggerated increase of the total insulin was observed in a patients with insulin autoimmune syndrome.
The diurnal changes of free insulin suggested us the usefulness of the determination of free insulin level for the control of diabetes with insulin treatment.
