Abstract
To investigate the biological effects of human insulin antibody, the effects of insulin antibody on the conversion of 2-3H-glucose were studied in isolated rat adipocytes.
Human insulin antibody was highly purified from the serum of an insulin-resistant diabetic patient, whose resistance was caused by insulin antibody, by using monocomponent insulin as the affinity chromatographic ligand. All studies were performed with less than 50μg/ml of IgG, a concentration at which pooled normal IgG did not affect glucose conversion in preliminary testing. At a concentration of 1.6μg/ml, the antibody suppressed the insulin effect on glucose conversion when insulin was present (p<0.01 or p<0.001). At the concentrations of 0.01 and 0.001μg/ml, the antibody stimulated glucose conversion when insulin was absent (p<0.02 or p<0.01). This stimulatory effect of antibody at 0.01 and 0.001μg/ml remained after trypsin treatment of the adipocytes (p<0.02 and p<0.02). The stimulatory effect without insulin was accompanied by an increase in the binding affinity of insulin receptors.
The results suggest that insulin antibodies act differently in diabetic patients with insulin resistance caused by insulin antibody, yielding a direct insulin-like stimulatory effect, as well as affecting the inhibition and the enhancement of insulin activity, as previously reported.
