The effect of corticosteroids on amyloid β precursor protein/amyloid precursor-like protein expression and processing in vivo

In this study, we have investigated the effect of altered corticosteroid levels on the expression and processing of the amyloid β precursor protein (A βPP) and its amyloid precursor-like protein (APLP) homologue in rat brain. Four groups of animals were used in the study: sham operated, adrenalectomised, and adrenalectomised treated with either dexamethasone or aldosterone, with the AβPP/APLP expression being determined by western blot analysis. While there were no changes in the levels of AβPP/APLP following adrenalectomy, treatment with dexamethasone, but not aldosterone, resulted in a marked increase in protein expression levels with the level of increase varying between the brain regions examined. Corticosteroids had a more marked effect on the particulate rather than the soluble form of the protein, thus suggesting that elevated glucocorticoids may also be adversely influencing AβPP/APLP processing.