PSEN1 and Alzheimer disease: Similarly, long term administration of exendin-4 (500 μg/kg/day for 9 months) failed to reduce Aβ plaque burden or Tau immunoreactivity in 12-month-old 3xTg-AD mice expressing human mutant PS1 (PS1M146V), human mutant APP (APPswe) and tau (tau P301L) protein [43].