Age effect on cell-transit time in mouse jejunal epithelium

Abstract

Epithelial cell renewal in the jejunum of CAF₁ mice was studied by observing the time for cells labeled with tritiated thymidine (1.5–2.0 µc/g body wt.) to pass from the crypt to the extrusion zone at the tip of the villus. Mice of three ages were studied: 93, 372, and 940 days. The total observed transit times were 44, 52, and 53 hr, respectively. The increase with age was the result of increase in both the crypt and villus transit times. Structural changes could not be made to account for the differences. The increase may be the result of a decreased rate of cell production in the crypts.