Relationship of insulin binding and insulin-stimulated tyrosine kinase activity is altered in type II diabetes.
The insulin receptor contains an alpha subunit with insulin binding properties and a beta subunit with insulin-stimulated tyrosine kinase function. Preparations containing insulin and insulinlike growth factor I (IGF-I) receptors were obtained from solubilized human red cell membranes by affinity chromatography. After separate assays for insulin binding and insulin-stimulated tyrosine kinase activities, a high degree of correlation was found between these activities in preparations from normals and diabetics. Identical studies using IGF-I as the ligand showed a lesser degree of correlation. We compared 24 normal subjects and 14 untreated type II diabetics and found significant diminution in the slope of the line coupling insulin binding and insulin-stimulated kinase activities in the diabetics. This difference was not observed in a similar study of IGF-I-related activities. Compared to normal controls, untreated type II diabetics have reduced tyrosine kinase activity stimulated per unit insulin binding.
D000328:Adult; D000368:Aged; D001667:Binding, Competitive; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D037102:Lectins; D046911:Macromolecular Substances; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood; D011505:Protein-Tyrosine Kinases / Q000097:blood*; D011972:Receptor, Insulin / Q000378:metabolism*; D012016:Reference Values
D006442:Glycated Hemoglobin; D007328:Insulin; D037102:Lectins; D046911:Macromolecular Substances; D011505:Protein-Tyrosine Kinases; D011972:Receptor, Insulin