The effect of lucanthone on the radiation response of intestinal stem cells in Chinese hamsters.

Crypt microcolony assay was used to determine the effect of lucanthone on the radiation response of intestinal stem cells in Chinese hamsters . The Dq of the crypt microcolony radiation--survival curve was maximally reduced by 205 rads when lucanthone injection preceded irradiation by 10 hours and was reduced by 140 rads when injection followed irradiation by 5 hours. On simultaneous injection and irradiation, Dq was reduced by only 20 rads; when injection and irradiation were separated by approximately 30 hours, Dq returned to the control value. Lucanthone never affected Do. Thus at non-toxic concentrations, lucanthone reversibly modifies cellular ability to accumulate and repair sublethal radiation damage without affecting radiation sensitivity.