RCAN1 and type 2 diabetes mellitus: We measured in vivo GSIS in mice overexpressing RCAN1.1 (henceforth referred to as RCAN1ox) as reduced GSIS is a hallmark in T2D individuals [14,15,20], and as RCAN1.1 is the major β-cell RCAN1 isoform with the greatest increase in db/db islets.