Increasing amyloid peptide precursor production and its impact on Alzheimer's disease.

Amyloid peptide precursor (APP) gene expression increases in the brains of patients with Alzheimer's disease (AD). Regulation of expression at the transcriptional and posttranscriptional levels contributes significantly to these increases. Polypeptide hormones stimulate the promoter of the APP gene resulting in increased levels of heterogeneous nuclear RNAs (hnRNA). Through splicing, these hnRNAs are processed into 3 or more mature APP RNAs. The amounts of each of these similar but nonidentical APP RNAs may yield ratios of APP proteins which are required for neuronal survival, pathogenesis of neurons and/or produce phenocopies of learning and memory mutants of Drosophila.