Hallén I P, Oskarsson A
Toxicology Division, Swedish National Food Administration, Uppsala, Sweden.
Biometals. 1995 Jul;8(3):231-6. doi: 10.1007/BF00143381.
The bioavailability of lead from various milk diets was studied in 14 day old suckling rats. Human milk, infant formula, cow's milk, rat milk and deionized water labeled with 203Pb were given to rat pups by gastric intubation. Animals were killed after 2 or 6 h and the radioactivity in the tissues was measured. At 2 h after administration the lead bioavailability, defined as lead uptake in the body, excluding the gastrointestinal tract, was 47% from water, 42% from human milk, 40% from infant formula, 31% from cow's milk and 11% from rat milk. After 6 h the bioavailability of lead was about 50% from water and human milk, 45% from infant formula and cow's milk, and 36% from rat milk. The blood lead levels in the pups reflected the total body uptake and were also correlated to the brain lead levels. Thus, rat pups given lead in human milk had approximately twice as high lead levels in blood and brain than pups given lead in rat milk. The intestinal absorption of lead was dependent on the milk diet given to the sucklings. In duodenum, the highest uptake of lead was found in rats given water or human milk, whereas in rats given rat or cow's milk the highest uptake of lead was found in ileum. The distribution of lead in cream, whey and casein fractions of the milk diets after in vitro labeling with 203Pb was also studied. The casein fraction in cow's and rat milk contained 90-96% of the total amount of lead in the diet.(ABSTRACT TRUNCATED AT 250 WORDS)
在14日龄的乳鼠中研究了不同奶类饮食中铅的生物利用度。用203Pb标记的人乳、婴儿配方奶粉、牛奶、大鼠乳和去离子水通过胃管喂给幼鼠。2小时或6小时后处死动物，测量组织中的放射性。给药后2小时，铅的生物利用度（定义为体内铅的摄取量，不包括胃肠道），水中为47%，人乳中为42%，婴儿配方奶粉中为40%，牛奶中为31%，大鼠乳中为11%。6小时后，水中和人乳中铅的生物利用度约为50%，婴儿配方奶粉和牛奶中为45%，大鼠乳中为36%。幼鼠的血铅水平反映了全身摄取量，也与脑铅水平相关。因此，摄入人乳中铅的幼鼠血液和脑中的铅水平大约是摄入大鼠乳中铅的幼鼠的两倍。铅的肠道吸收取决于给乳鼠的奶类饮食。在十二指肠中，给水或人乳的大鼠铅摄取量最高，而给大鼠乳或牛奶的大鼠，铅摄取量最高的部位是回肠。还研究了用203Pb进行体外标记后，奶类饮食中铅在乳脂、乳清和酪蛋白部分的分布。牛奶和大鼠乳中的酪蛋白部分含饮食中铅总量的90 - 96%。（摘要截短于250字）
