Hoffman D J, Heinz G H, Krynitsky A J
U.S. Fish and Wildlife Service, Patuxent Wildlife Research Center, Laurel, Maryland 20708.
J Toxicol Environ Health. 1989;27(2):263-71. doi: 10.1080/15287398909531296.
Studies were conducted with mallard (Anas platyrhynchos) ducklings to determine the effects of excess dietary selenium (Se) on hepatic glutathione concentration and associated enzymes, and lipid peroxidation. Day-old ducklings were fed 0.1, 10, 20, or 40 ppm Se as seleno-DL-methionine or sodium selenite for 6 wk. Selenium from selenomethionine accumulated in a dose-dependent manner in the liver, resulting in a decrease in the concentration of hepatic-reduced glutathione (GSH) and total hepatic thiols (SH). These effects were accompanied by a dose-dependent increase in the ratio of oxidized glutathione (GSSG) to GSH, and an increase in malondialdehyde concentration as evidence of lipid peroxidation. Hepatic and plasma GSH peroxidase activity was initially elevated at 10 ppm Se as selenomethionine, whereas GSSG reductase activity was elevated at higher dietary concentrations of Se. Selenium from sodium selenite accumulated in the liver to an apparent maximum at 10 ppm in the diet, resulting in an increase in hepatic GSH and GSSG accompanied by a small decrease in total hepatic SH. Sodium selenite resulted in an increase in hepatic GSSG reductase activity at 10 ppm and in plasma GSSG reductase activity at 40 ppm. A small increase in lipid peroxidation occurred at 40 ppm. These findings indicate that excess dietary Se as selenomethionine has a more pronounced effect on hepatic glutathione metabolism and lipid peroxidation in ducklings than does selenite, which may be related to the pattern of accumulation. Effects of Se as selenite appear to be less pronounced in ducklings than reported in laboratory rodents. The effects of selenomethionine, which occurs in vegetation, are of particular interest with respect to the health of wild aquatic birds in seleniferous locations.
对绿头鸭（Anas platyrhynchos）雏鸭进行了研究，以确定过量的膳食硒（Se）对肝脏谷胱甘肽浓度及相关酶以及脂质过氧化的影响。将1日龄雏鸭分别喂食含0.1、10、20或40 ppm硒的硒代-DL-蛋氨酸或亚硒酸钠，持续6周。硒代蛋氨酸中的硒以剂量依赖性方式在肝脏中蓄积，导致肝脏中还原型谷胱甘肽（GSH）浓度和肝脏总硫醇（SH）含量降低。这些影响伴随着氧化型谷胱甘肽（GSSG）与GSH比例的剂量依赖性增加，以及丙二醛浓度的增加，作为脂质过氧化的证据。当硒代蛋氨酸的硒含量为10 ppm时，肝脏和血浆中的谷胱甘肽过氧化物酶活性最初升高，而在较高膳食硒浓度下，GSSG还原酶活性升高。亚硒酸钠中的硒在日粮中10 ppm时在肝脏中蓄积至明显最大值，导致肝脏GSH和GSSG增加，同时肝脏总SH略有下降。亚硒酸钠在10 ppm时导致肝脏GSSG还原酶活性增加，在40 ppm时导致血浆GSSG还原酶活性增加。在40 ppm时脂质过氧化略有增加。这些发现表明，与亚硒酸盐相比，过量的膳食硒代蛋氨酸对雏鸭肝脏谷胱甘肽代谢和脂质过氧化的影响更为显著，这可能与蓄积模式有关。亚硒酸盐对雏鸭的影响似乎不如在实验室啮齿动物中报道的那样明显。植被中存在的硒代蛋氨酸的影响对于含硒地区野生水鸟的健康特别令人关注。
