THE PROLIFERATIVE STATUS OF INTESTINAL EPITHELIAL CLONOGENIC CELLS: SENSITIVITY TO S PHASE SPECIFIC CYTOTOXI CAGENTS

Abstract

High concentrations of 3H thymidine and cytosine arabinoside (Ara-C) were used to selectively kill cells in the crypts of Lieberkuehn [mouse] that are synthesizing DNA. The effect of these agents on the number of regenerating microcolonies seen 3 1/2 days after a range of radiation doses indicates that a majority of the clonogenic cells are proliferating rapidly and that the slowly proliferating cells at the base of the crypt do not represent the whole clonogenic population.