No radioadaptive response to micronucleated polychromatic erythrocyte (MN-PCE) induction in murine peripheral blood in vivo.

The effect of conditioning pretreatment with 0.025 Gy of gamma rays on micronucleated polychromatic erythrocyte (MN-PCE) induction by 1.0 or 0.1 Gy of gamma rays was determined in murine peripheral blood. The adaptive and challenge doses as well as the timing of their administration were taken from a previously reported experiment [Farooqi and Kesavan (1992). Mutat Res 302:83-89]. The response was determined by the strategy of measuring the area below the curve (ABC) of MN-PCE induction vs. time. This strategy permits one to determine an index of total damage and to establish if conditioning exposure affects the timing of MN-PCE appearance in the blood stream, which in turn could cause an apparent difference in response between the conditioned and the unconditioned groups at specific times. The results indicate that low dose gamma ray pretreatment does not protect against MN-PCE induction by the challenge gamma ray dose, and that there was no change on the kinetics of MN-PCE appearance in peripheral blood.