As schematized in Figure 6, hippocampal GRP78 expression was significantly increased in diabetic rats; however, treatment with NaHS clearly decreased the protein expression of hippocampal GRP78 in diabetic rats, indicating the response of diabetes to hippocampal ER stress and the suppressive function of NaHS on STZ-induced hippocampal ER stress. This evidence concerns the gene HSPA5 and diabetes mellitus.