DNA, RNA, and protein synthesis in brain, liver, and kidneys of asymptomatic methylmercury treated rats

Abstract

Total mercury levels increased with dose in the brain, liver, and kidneys of adult male rats treated with methylmercury hydroxide. The distribution of mercury among these organs was constant over a seven day period in animals treated with 10 mg/kg/day. The brain, liver, and kidneys of animals treated with a total dose of 70 mg/kg contained 10, 113, and 260 ppm of mercury, respectively. These animals displayed no neurological signs of alkylmercury poisoning. Organ-specific changes in total content and synthesis of DNA, RNA, and protein occurred as the tissue mercury burden increased. In general, macromolecular synthesis was enhanced in the brain and liver, while inhibitory effects were predominate in the kidneys. The synthesis of proteins was more sensitive to mercury than nucleic acids. Total ribosome content and their distribution among their functional cytoplasmic compartments varied with alterations in protein synthesis activity, suggesting disturbances at the level of gene translation. The capacity to synthesize DNA was conserved in the liver and kidneys at elevated tissue mercury levels. The evidence presented advances the hypothesis that disturbances in protein synthesis is a fundamental aspect of alkylmercury poisoning.