APP and Alzheimer disease: Both stress-level glucocorticoid administration in 3xTg-AD mice [65] and stress induction in wild-type rats [66] increase the levels of APP and the β-APP cleaving enzyme 1 (BACE1), which in turn increases amyloidogenic processing of APP and results in elevated levels of APP-derived fragments (C99 and C83) and Aβ peptides.