In vivo effects of chronic contamination with 137 cesium on testicular and adrenal steroidogenesis

More than 20 years after Chernobyl nuclear power plant explosion, radionuclids are still mainly bound to the organic soil layers. The radiation exposure is dominated by the external exposure to gamma-radiation following the decay of 137Cs and by soil-to-plant-to-human transfer of 137Cs into the food chain. Because of this persistence of contamination with 137Cs, questions regarding public health for people living in contaminated areas were raised. We investigated the biological effects of chronic exposure to 137Cs on testicular and adrenal steroidogenesis metabolisms in rat. Animals were exposed to radionuclide in their drinking water for 9 months at a dose of 6,500 Bq/l (610 Bq/kg/day). Cesium contamination decreases the level of circulating 17β-estradiol, and increases corticosterone level. In testis, several nuclear receptors messenger expression is disrupted; levels of mRNA encoding Liver X receptor α (LXRα) and LXRβ are increased, whereas farnesoid X receptor mRNA presents a lower level. Adrenal metabolism presents a paradoxical decrease in cyp11a1 gene expression. In conclusion, our results show for the first time molecular and hormonal modifications in testicular and adrenal steroidogenic metabolism, induced by chronic contamination with low doses of 137Cs. (orig.)