GCG and diabetes mellitus: Several studies have also shown that exogenousadministration of IAPP at supraphysiological doses inhibits glucagon secretion [8–11].IAPP of the human form may lead to fibril formation, which causes amyloiddeposition in the islets resulting in β-cell dysfunction and diabetes [12–14].We have previously shown that mice with β-cell specific overexpression of thehuman form of IAPP (hIAPP) have defective insulin secretion and disturbed islettopography with centrally located glucagon producing α-cells [15, 16].