p53 accumulation in various organs of rats after whole-body exposure to low-dose X-ray irradiation.

We report the induction of wild-type p53 protein accumulation in various organs within 12 h of exposure to X-ray irradiation at low doses (10, 25 or 50 cGy) in rats. The levels of p53 in some organs of irradiated rats were increased about 2- to 3-fold in comparison with the basal p53 levels in non-irradiated rats. Differences in the levels of p53 induction after low-dose X-ray irradiation were observed in the small intestine, bone marrow, brain, liver, adrenal gland, spleen, hypophysis and skin. In contrast, there was no obvious accumulation of p53 protein in the testis and ovary. Thus, the induction of cellular p53 accumulation by low-dose X-ray irradiation in rats seems to be organ-specific. We consider that cell type, and interactions with other signal transduction pathways of the hormone system, immune system and nervous system may contribute to the variable induction of p53 by low-dose X-ray irradiation.