Heterogeneous distribution of 125I-insulin binding sites in the liver of fed and fasted mice.

A microradioautography made three min. after intravenous injection of 125I-insulin was used to study the distribution of insulin binding sites in the liver of fed and fasted mice. A substantial specific binding of 125I-insulin to liver parenchymal cells could be seen in these mice, whereas radioautographs from animals injected with 125I-insulin plus an excess of unlabelled insulin showed only trace amounts of silver grains. In both fed and fasted mice, a density gradient of the binding from the periportal zone to the perivenous zone was evident, and the binding in each zone was significantly higher in the fasted mice than in the fed mice.