title: Effects of antiinsulin receptor autoantibody on the metabolism of rat adipocytes.
abstract: We have studied the effects of the serum from a patient with an unusual form of diabetic syndrome with extreme insulin resistance on the metabolism of rat adipocytes in vitro. This serum and IgG fractions from it inhibited the [125I]insulin binding to isolated adipocytes and stimulated the 2-deoxyglucose uptake, glucose oxidation, and the incorporation of amino acids into protein. In addition, these fractions inhibited the lipolysis induced by beta 1-24 ACTH in isolated adipocytes. The insulin-like effects of this serum and the effects of insulin were not additive at their maximal concentrations. The inhibition of [125I]insulin binding was due to a decrease in receptor affinity rather than to a change in receptor number by Scatchard plot analysis. Both the inhibition of insulin binding and the insulin-like effects on rat adipocytes were neutralized by antihuman IgG. In addition, these insulin-like effects were abolished by trypsin treatment of adipocytes. These facts suggest that this serum has a circulating antibody directed at or near the insulin receptor itself and that this antibody mimics the insulin effect on rat adipocytes by binding to the insulin receptor in vitro.
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D000818:Animals; D001323:Autoantibodies / Q000302:isolation & purification; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000302:isolation & purification; D007328:Insulin / Q000031:analogs & derivatives / Q000378:metabolism; D008066:Lipolysis; D008297:Male; D014176:Protein Biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D011972:Receptor, Insulin / Q000276:immunology* / Q000378:metabolism
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D007328:Insulin; C008147:insulin, iodo-; D011972:Receptor, Insulin