Rouleau C, Tjälve H, Gottofrey J, Pelletier E
University of Québec at Rimouski, Department of Oceanography, Canada.
Pharmacol Toxicol. 1994 Apr-May;74(4-5):271-9. doi: 10.1111/j.1600-0773.1994.tb01111.x.
The effects of humic acids, which are natural metal-complexing compounds, and potassium ethylxanthate, sodium diethyldithiophosphate, sodium dimethyldithiocarbamate, and sodium diethyldithiocarbamate, which are sulphur-containing man-made chelating agents, on the uptake and tissue distribution of 54Mn(II) were studied in brown trout (Salmo trutta). Fish were exposed for 7 days to 0.1 microgram Mn(II).l-1 as MnCl2 (1 microCi 54MN.l-1) with or without chelating agents. Examination of the partition of Mn between octanol and a Tris-HCl buffer in the presence of these compounds was also performed. Humic acids had only small effects on Mn uptake and distribution in trout, probably because of the low stability of Mn-humate complexes. Partition of Mn in the presence of potassium ethylxanthate, sodium diethyldithiophosphate, sodium dimethyldithiocarbamate, and sodium diethyldithiocarbamate between octanol and Tris-HCl buffer showed formation of lipophilic complex with the latter two compounds, but not with the former. However, these four chelating agents all decreased Mn uptake in the trout by 40-45%. These substances also changed the distribution of Mn within the fish, with a higher proportion of the metal being present in some visceral organs and a smaller proportion being localized in some non-parenchymateous tissues, such as skins, fins and bones. The mechanisms underlying these effects are not known. However, the interaction of chelating agents with the Mn, although weak, may have partially withdrawn the metal from the uptake process in the gills. The redistribution of Mn in the fish may be due to the binding of the metal to complexing compounds which have reached the intestinal lumen.(ABSTRACT TRUNCATED AT 250 WORDS)
腐殖酸是天然的金属络合化合物，而乙基黄原酸钾、二乙基二硫代磷酸钠、二甲基二硫代氨基甲酸钠和二乙基二硫代氨基甲酸钠是含硫的人造螯合剂，研究了它们对褐鳟（Salmo trutta）摄取和组织分布54Mn(II)的影响。将鱼暴露于含或不含螯合剂的0.1微克Mn(II).l-1的MnCl2（1微居里54MN.l-1）中7天。还进行了在这些化合物存在下Mn在辛醇和Tris-HCl缓冲液之间的分配研究。腐殖酸对鳟鱼摄取和分布Mn的影响很小，可能是因为Mn-腐殖酸盐络合物的稳定性较低。在乙基黄原酸钾、二乙基二硫代磷酸钠、二甲基二硫代氨基甲酸钠和二乙基二硫代氨基甲酸钠存在下，Mn在辛醇和Tris-HCl缓冲液之间的分配表明，后两种化合物形成了亲脂性络合物，而前两种则没有。然而，这四种螯合剂均使鳟鱼对Mn的摄取减少了40-45%。这些物质还改变了Mn在鱼体内的分布，使该金属在一些内脏器官中的比例更高，而在一些非实质组织（如皮肤、鳍和骨骼）中的比例更小。这些影响的潜在机制尚不清楚。然而，螯合剂与Mn的相互作用虽然较弱，但可能部分地从鳃的摄取过程中提取了该金属。鱼体内Mn的重新分布可能是由于该金属与到达肠腔的络合化合物结合所致。（摘要截断于250字）
