Reduced proteins in temporal cortex in Alzheimer's disease: an electrophoretic study.

Cytoplasmic and pellet fractions from post-mortem temporal cortex from eight cases of neuropathologically confirmed Alzheimer's disease, one case of cerebrovascular dementia, and five controls were examined by sodium dodecylsulphate-polyacrylamide gel electrophoresis. No differences were observed in the cytoplasmic proteins from the five controls and the case of cerebrovascular dementia. In five cases of Alzheimer's disease with neurone loss, there was a major loss of a cytoplasmic 55,000-dalton protein identified as tubulin and variable reductions in cytoplasmic proteins of molecular weights of 28,000, 30,000, 92,000, and 200,000 daltons. Three cases of Alzheimer's disease had no detectable neurone loss; two of these cases had protein patterns indistinguishable from the controls and one showed some reduction in soluble tubulin only. These results indicate that decreases of particular proteins in the temporal cortex in Alzheimer's disease may be associated with neurone loss.