The effect of a single injection of cytosine arabinoside on cell population kinetics in the mouse jejunal crypt.

The early effects of a single injection of cytosine arabinoside (ara-C) on cell population kinetics in the jejunal crypt of the mouse were studied using autoradiography with tritiated thymidine, and metaphase arrest with vincristine. Ara-C had three main effects on crypt cells: a block of cells near the transition from G1 to S, death of nearly all cells in S, and a temporary block of the survivors, which remained viable and were able to proceed through the cell cycle. Throughout the crypt there was a decrease in cell cycle time and an increase in growth fraction. Although changes in proliferative rate were highest in the lowest part of the crypt it was not possible to show that crypt repopulation originated only from basal crypt cells, and the data are consistent with repopulation from the faster cycling cells in the proliferative compartment.