PAX6 and Hyperglycemia: The use here of the efficient and selective Pdx1CreERT driver line (23, 24, 31) led to the more rapid (within days of tamoxifen treatment) and severe (>50 mm) hyperglycemia than observed previously after Pax6 deletion either globally (18) or in β cells using the more promiscuous rat insulin promoter 2 (RIP2) Cre driver (19).