锰对大鼠硒代谢的影响

鉴于贫硒与克山病发病有密切关系以及一些病区的人群既贫硒又富锰,本文研究了锰对大鼠硒代谢的影响。经腹腔给大鼠注射40mg/kg氯化锰5周,致血清和心肌锰含量明显增高,而血清和心肌硒含量以及全血和心肌谷胱甘肽过氧化物酶活性却显著降低。组织锰含量与硒含量和谷胱甘肽过氧化物酶活性呈负相关。在给予氯化锰的第7天,经胃管给予~(75)硒,锰组大鼠在服~(75)硒之后7天中总排硒量显著高于对照组大鼠,主要是由于锰促进慢相尿硒排泄所致。结果表明,锰对硒代谢有明显影响,即通过增加硒排泄量而致血、心肌硒含量和含硒酶活性显著降低。

INFLUENCE OF MANGANESE ON SELENIUM METABOLISM IN RATS

The effects of manganese on selenium content and glutathione peroxidaseactivity in blood and myocardium, and on selenium excretion in growing ratswere studied to ferret out the interaction of the two essential trace elements.Manganese dichloride (40mg/kg of MnCl2.4H2O) was administered daily to a group of 17 rats for 35 days intraperitoneally. An obvious increase in manganese content in serum and myocardium was induced. However, selenium levels in the two tissues of manganese-treated rats were significantly lower than the controls. From the 14th day on, glutathione peroxidase activities in whole blood of manganese-treated rats were below the controls, and on the 35th day, the activities of the selenium-containing enzyme in blood and myocardium were reduced by 29.33% (P<0.001) and 20.48% (P<0.001) respectively. Negative correlations between manganese and selenium and between manganese and glutathione peroxidase in the two tissues were found.75Se-selenite was given orally to another group of 6 rats after treatment with manganese for 7 days, and a higher level of 75Se in urine was observed during the slow phase of excretion.In conclusion, excessive exposufe to manganese increases selenium excretion,thereby depleting tissue stores of selenium and the activities of selenium-containing enzyme.