下列降血糖藥與作用機轉的配對，何者錯誤？
pioglitazone—peroxisome proliferator-activated receptor gamma（PPAR-γ）agonist
metformin—AMP-activated protein kinase（AMPK）activator
exenatide—glucagon-like peptide-1（GLP-1）receptor agonist
empagliflozin—sodium-glucose co-transporter 2（SGLT2）activator
