Insulin receptors in adipocytes of non-diabetic and diabetic subjects. Preliminary report

Abstract

We have measured insulin binding to human adipocytes isolated from subcutaneous adipose tissue removed during surgery in normal and insulin-independent diabetics. Collagenase digestion, 125I-monoiodoinsulin and Scatchard's plot were employed to analyze the results. Different kinetic patterns emerged together with differences in the dissociation constant and receptor numbers: in normal subjects K1 was 4 X 10(-9) moles/1 and K20.5 X 10(-8) moles/1, and in diabetic subjects K1 was 2.24 X 10(-9) moles/1 and K2 0.52 X 10 10(-8) moles/1; the two classes of receptors were 100,000 and 300,000 per cell in normals and 50,000 and 180,000 in diabetics. It was clear that even slight diabetes leads to receptor deficiency in adipocytes, though it could not be determined whether this a primary, perhaps genetic, defect or secondary to antibody damage, as suggested by some workers. Feed-back between circulating insulin and specific receptor availability in cells is another possibility.