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 beta precursor protein (A beta PP) and its a myloid 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 A beta PP/APLP expression being determined by western blot analysis. While there were no changes in the levels of A beta PP/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 A beta PP/APLP processing. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.