Binding of 125I-labeled glucagon and glucagon-stimulated accumulation of adenosine 3‘:5‘-monophosphate in isolated intact rat hepatocytes. Evidence for receptor heterogeneity.

Abstract

The binding of "'I-labeled glucagon and its relationship to the glucagon-stimulated production of adenosine 3'5'.monophosphate were investigated in isolated rat hepatocytes at 37°C.The binding data obtained when steady state was approached.or from association and dissociation experiments, could not be adequately described on the basis of one homogeneous population of receptors.Assuming two classes of saturable binding sites, the data could be explained by the existence of approximately 2 x lo4 sites/cell with a dissociation constant (K,,) of about 0.7 nM and approxi-