Accumulation of amyloid-beta protein in exocrine glands of transgenic miceoverexpressing a carboxyl terminal portion of amyloid protein precursor

Amyloid-beta protein (A beta) and its precursor (beta PP) play important ro les in the pathogenesis of Alzheimer disease and inclusion-body myositis. I n humans, A beta deposits are found in brain, skeletal muscle, and skin. Th erefore, we have investigated possible A beta deposits in multiple tissues of two transgenic mouse lines overexpressing the signal plus A beta-bearing 99-amino acid carboxyl terminal sequences of beta PP under the control of a cytomegalovirus enhancer/beta-actin promoter. One of the lines developed A beta-immunoreactive intracellular deposits consistently in the pancreas a nd lacrimal gland, and occasionally in gastric, DeSteno's, and lingual glan ds. Although the A beta deposits increased during ageing and degenerative c hanges of the tissues were observed, little or no extracellular A beta depo sits were observed up to the age of 25 months. These lines of transgenic mi ce are useful for studying the molecular mechanisms of development and clea rance of intracellular A beta deposits.