The effects of administering methylmercury in combination with ethanol in the rat

Methylmercury (MeHg) is a potent neurotoxicant and nephrotoxicant in several animal species including humans. Although the in vivo toxicity of MeHg per se is well known, the interaction between MeHg and other pollutants and with nutritional factors is not well understood. Since ethanol (EtOH) is a widely consumed toxicant which has been shown to enhance the histopathologic effects of MeHg on renal tissues, a study was undertaken to examine the effects of the combined administration to rats of MeHg and EtOH on renal function and on mercury distribution in body tissues. Forty-eight rats were divided into 6 treatment groups of 8 rats each. Rats in groups 1, 2 and 3 were given feed ad libitum, a restricted liquid diet of 70 mL/d or distilled water orally, respectively. Rats in groups 4, 5 and 6 were given 1.5 mg MeHg/kg bw, 2.0 g EtOH/kg bw, or 1.5 mg MeHg + 2.0 g EtOH/kg bw, respectively, by oral gavage daily for 45 d. All rats except those in group 1 (ad libitum) were fed 70 mL of liquid diet/d for the entire study period. The ingestion of MeHg + EtOH in combination induced a greater increase in renal weight compared to treatment with either MeHg + EtOH alone. Only those rats given MeHg in combination with EtOH exhibited oliguria and elevated blood urea nitrogen levels. Despite this antidiuresis, urinary concentrating ability was impaired in those rats given both MeHg and EtOH. In contrast, the ingestion of MeHg by itself caused the most rapid loss of glucose in urine.(ABSTRACT TRUNCATED AT 250 WORDS)