Differential responses of certain brain phosphoesterases to aluminium in dietary protein adequacy and inadequacy

The aluminium-induced neurotoxic consequences include, among other factors, dephosphorylation, phosphorylation as well as hyperphosphorylation of spec ific macromolecules. Accordingly, activities of phosphoesterases were measu red in different regions of rat brain, maintained with either adequate or i nadequate protein diet, following aluminium exposure. Male Wistar rats weig hing 80-100 g were treated with aluminium chloride at a dose of 15% of the LD50 for 4 weeks. In different regions of the brain of aluminium-exposed ra ts, significant variation in both phosphomonoesterase and phosphodiesterase activities have been recorded. These alterations were found to be varied w hen the rats were subjected to dietary protein insufficiency. These finding s demonstrate the specificity of aluminium on different phosphoesterases. T hese regional variations may be attributed to the accumulated level of alum inium or may be due to cellular localization of these enzymes and linked to whether the enzymes are compartmentalized with different aluminium hydrati on species. (C) 2001 Elsevier Science Ltd. All rights reserved.