van den Hoek J, ten Have M H, Gerber G B, Kirchmann R
Radiat Res. 1985 Jul;103(1):105-13.
Two lactating cows were given tritiated hay containing organically bound tritium (OBT) only for about 4 weeks. Tritium activity was determined in milk fat, casein, lactose, milk water, and whole milk. In one cow, milk was sampled for approximately 450 days, covering two lactation periods. At steady state, specific tritium activities in casein, lactose, and milk water were 58, 10, and 11%, respectively, of those in milk fat. Some OBT was converted into THO during catabolism and entered the body water pool. This 3H source accounted for nearly 40% of tritium in lactose, but in casein and milk fat about 97% of tritium was derived from ingested OBT. Comparison of the specific activity of milk constituents with the specific activity of ingested hay showed the following values: 0.84 for milk fat, 0.49 for casein, 0.05 for lactose, 0.10 for milk water. About one-half of the tritium transferred to milk was found in organic milk constituents and the other half in milk water. Decrease of tritium activity with time could be represented by three components with different half-lives for the organic milk constituents. Those for milk fat and casein were quite similar, with a slow component of nearly 3 months.
给两头泌乳奶牛仅饲喂含有机结合氚（OBT）的氚标记干草约4周。测定了乳脂肪、酪蛋白、乳糖、乳中的水和全脂乳中的氚活度。对其中一头奶牛的乳进行了约450天的采样，涵盖两个泌乳期。在稳定状态下，酪蛋白、乳糖和乳中的水的比活度分别为乳脂肪中比活度的58%、10%和11%。一些OBT在分解代谢过程中转化为THO并进入机体水池。这种3H来源占乳糖中氚的近40%，但在酪蛋白和乳脂肪中，约97%的氚来自摄入的OBT。乳成分的比活度与摄入干草的比活度比较得出以下值：乳脂肪为0.84，酪蛋白为0.49，乳糖为0.05，乳中的水为0.10。转移到乳中的氚约一半存在于乳的有机成分中，另一半存在于乳中的水中。有机乳成分中氚活度随时间的降低可用具有不同半衰期的三个成分来表示。乳脂肪和酪蛋白的半衰期非常相似，有一个近3个月的慢成分。
