Pigs are commonly used as a large animal model in diabetes research since they are anatomically and physiologically very similar to humans,12 and oral glucose tolerance test (OGTT) can be carried out in the same way with pigs as with humans.13 The aim of the present experiment was, with the aid of ex vivo autoradiography and radioactively labelled exendin-4, to quantitatively describe the distribution of GLP-1Rs in pancreas and gastrointestinal tract and to assess GLP-1R occupancy by endogenous GLP-1 in vivo during OGTT in pigs. This evidence concerns the gene GLP1R and diabetes mellitus.