GPBAR1 and type 2 diabetes mellitus: Both modulation of bile acid metabolism and utilisation of FXR- and TGR5-agonists, therefore, represent attractive though challenging, therapeutic options in type 2 diabetes, non-alcoholic fatty liver disease (NAFLD), and non-alcoholic steatohepatitis (NASH) [94–97], which are, nevertheless, complicated by the expression of FXR and TGR5 in many tissues.