Increase in phospholipase C-delta 1 protein levels in aluminum-treated ratbrains

The effect of administration of aluminum to rats on the level of three phos pholipase C (PLC) isozymes (beta 1, gamma 1, and delta 1) was assessed in a variety of brain tissues. After exposure to aluminum, a statistically sign ificant increase in malondialdehyde, an index of lipid peroxidation, was ob served. In addition, there was a significant reduction in the catalytic act ivity of low molecular weight phosphotyrosine phosphatase, which loses its activity during oxidative stress. This suggests that oxidative stress is in duced in brain tissues exposed to aluminum. The protein level of PLC-delta 1, but not that of PLC-beta 1 or -gamma 1, was significantly increased in b rains where oxidative stress had been induced. The total PLC activity in al uminum-treated rat brains was significantly higher than that in control bra ins. These results suggest that PLC-delta 1 protein levels in brain tissues are increased by the induction of oxidative stress, giving an explanation for its up-regulation in Alzheimer's disease. (C) 2000 Academic Press.