In agreement, a high-fat diet that elevates glucose and corticosterone in mice activates serum-glucocorticoid-regulated kinase 1 (SGK1) and GSK3β to promote tau hyperphosphorylation, neurodegeneration, and impaired spatial learning and memory in these mice, and SGK1 is also activated in the hippocampus of human brains with AD (27). Here, GSK3B is linked to Alzheimer disease.