Ammonia induced decrease in glial fibrillary acidic protein in cultured astrocytes.

Previous studies of human hepatic encephalopathy (HE) have shown decreased levels of glial fibrillary acidic protein (GFAP) in Alzheimer type II astrocytes. In view of the important role of ammonia in the pathogenesis of HE, we carried out immunocytochemical and enzyme-linked immunosorbent assay (ELISA) studies on the effect of ammonium chloride (10 mM) on GFAP content in primary astrocyte cultures. There was a 39% loss of GFAP after a four day treatment. There was no fall in total cell protein. Potential mechanisms for this apparent selective loss of GFAP are discussed.