Chen R W, Vasey E J, Whanger P D
J Nutr. 1977 May;107(5):805-13. doi: 10.1093/jn/107.5.805.
The accumulations of zinc in liver and kidneys of rats fed various dietary levels of this element was investigated. Zinc started to accumulate in rat liver when 1,000 ppm or higher levels of this element were fed in the diet, but not when the dietary zinc level was 500 ppm less. Almost all of the accumulated zinc in the soluble fraction was found to be present in the metallothionein (MT) fractions. When rats were fed a diet supplemented with 2,000 ppm, zinc, the metal rapidly accumulated in MT in the liver and kidneys. The accumulated zinc was, however, depleted to the pre-supplementation level after only 3 days of feeding a zinc deficient diet. While rats were fed the zinc deficient diet, in which the element was simultaneously depleted from MT, significant increased excretion of the metal occurred in the feces urine. No evidence was found to indicate that zinc was excreted in the bile in association with MT. It was therefore concluded that MT is probably, as one of its possible biological roles, more involved in accumulation of excessive zinc rather than in storage of the metal for later utilization.
研究了给大鼠喂食不同膳食锌水平后，锌在大鼠肝脏和肾脏中的蓄积情况。当饮食中锌含量为1000 ppm或更高时，锌开始在大鼠肝脏中蓄积，但当饮食锌水平低于500 ppm时则不会。几乎所有可溶部分中蓄积的锌都存在于金属硫蛋白（MT）部分。当给大鼠喂食添加了2000 ppm锌的饮食时，这种金属迅速在肝脏和肾脏的MT中蓄积。然而，在喂食缺锌饮食仅3天后，蓄积的锌就降至补充前的水平。当给大鼠喂食缺锌饮食时，锌同时从MT中耗尽，粪便和尿液中该金属的排泄量显著增加。没有证据表明锌与MT结合通过胆汁排泄。因此得出结论，MT作为其可能的生物学作用之一，可能更多地参与过量锌的蓄积，而不是为后续利用而储存该金属。
