Cell Population Kinetics in the Intestine of Continuously Irradiated Mice, Using Double-Labelling Autoradiography

Abstract
A Cl4-, H3-TdR double-labeling method was utilized to study the cell population changes in the epithelium of the ileum in mice continuously irradiated for 5 days at 50, 84, or 176 rads/day. The following conclusions were reached. The duration of DNA synthesis in control animals is 6.4[plus or minus]0.4 hours, and of mitosis, 0.4 hour. No major changes occur in the duration of DNA synthesis or of mitosis at the dose rates tested. The number of cells/crypt is similar in the control and irradiated animals. A large amount of cell death and loss occurs at the dose levels examined. An enhanced cell production in indicated; this is probably effected by an increase in the number of proliferating cells/crypt or by a shortening of the cell cycle or by both.