INSR and Alzheimer disease: The ICV administration of STZ has been reported to produce similar characteristic pathology of sporadic AD such as altered glucose metabolism, oxidative stress, synaptic dysfunction, protein kinases such as protein kinase B/C, glycogen synthase-synthase-3β (GSK-3β) activation, tau hyperphosphorylation, Aβ deposition of Akt/PKB, insulin receptor (IR) signaling molecule, and insulin resistance in brain39.