CALB1 and Hyperglycemia: In contrast, 13-months-old GK rats, exhibiting more severe fasting hyperglycemia than 30-week-old OLETF rats, reportedly showed type 2 diabetes progression-dependent decreases in NeuN-positive cells in the cerebral cortex, glutamic acid decarboxylase-67-positive cells in the striatum, and calbindin-positive cells in the cerebral cortex and striatum [40,53].