Age-related changes in 3H-uridine uptake in the mouse.

The uptake of a nucleic acid precursor as related to age was studied in mice. Newborn, young (3-month-old) and old (18 to 24-months-old) mice were given 3H-uridine orally through a plastic tube and sacrificed 4 and 21 hours later. Uptake was studied autoradiographically in nerve cells of the fifth layer of parietal cortex, the epithelial cells of the choroid plexus, the hepatocytes of the liver and the epithelium of the small intestine. While uptake decreased in all tissues with age, this was significant only after 4 hours. This decrease indicates that impaired nucleic acid metabolism may be related to aging.