WHOLE-BODY AUTORADIOGRAPHIC ANALYSIS OF THE IN-VIVO DISTRIBUTION OF GLUCAGON RECEPTORS IN MICE

In the present study, the histologic distribution of glucagon receptor s in the mouse was studied by in vivo whole body radioautography. Male mice were injected intravenously with I-125-labeled glucagon in the a bsence of and, in the presence of, excess unlabeled glucagon. Three, 6 , 15 and 30 min after injection, the animals were perfused and subject ed to radioautographic procedures. The results demonstrated that only the liver had a very high level of specific glucagon binding. Low leve l of specific glucagon binding was observed in the stomach, small inte stine. heart, kidney cortex. adipose tissue and spleen. These quantita tive results from in vivo whole body radioautography did not always co rrespond to those from the quantification of mRNA expression. This see ms to support a suggestion that glucagon receptor expression is modula ted at a step after mRNA formation. High level of non-specific glucago n binding was observed in the kidney, thyroid, sublingual and submandi bular glands and seminal vesicle.