APP and Alzheimer disease: The effects of WD on brain levels of the insulin signaling pathway components, p-IRS-1(Ser616), p-Akt(473), and p-GSK-3β(Ser9), and on neuropathological AD biomarkers, p-Tau(Thr231) and APP/Aβ levels, were analyzed in animals at 4, 8, 12, and 16 months of age (animal groups 4M, 8M, 12M, and 16M).