The present study was conducted to elucidate the effects of pancreatic amylase on plasma insulin, glucagon, and glucose levels during an intraduodenal glucose tolerance test (IDGTT), in healthy pigs and pigs with STZ-induced type 1-like and type 2-like diabetes mellitus, and investigate the possible direct effects of amylase on pancreatic beta-cells in the well-characterised, rat clonal, insulin-secreting beta-cell line, BRIN-BD11 [24]. Here, GCG is linked to diabetes mellitus.