van den Hoek J, ten Have M H, Gerber G B
Health Phys. 1983 Feb;44(2):127-33. doi: 10.1097/00004032-198302000-00003.
Two lactating Friesian cows received tritiated water (19 nCi of tritium per ml) to drink for 25 days. Urine and milk samples were collected and analyzed for tritium content. Plateau levels in milk water, and in milk fat, lactose and casein were reached in about 18 days. Tritium concentration in milk water and urine water was about 82% that in drinking water, indicating dilution with water from food and metabolic processes, and as a result of exchange through lungs and skin. At steady state, tritium activity in milk fat, lactose and casein was about 30, 28 and 15% of that in drinking water on a weight basis; at this time, about 1.5% of the daily ingested tritium appeared in one litre of milk in both animals. Comparison of the specific activity of the various milk constituents with the specific activity of the body water showed that the highest tritium incorporation occurred in lactose (0.58), followed by milk fat (0.36) and casein (0.27). Tritium incorporation in milk dry matter (0.45) is considerably higher than in most tissue components of several mammalian species after continuous ingestion of THO as reported in the literature. Tritium levels fell rapidly in milk and urine after the administration of THO was stopped, with half-times of around 4 days for the rapid components in all milk constituents. A slow component of 44 days, 225 days and 24 days half-time was found in milk water, milk fat and casein respectively.
两头泌乳期的弗里斯兰奶牛饮用含氚水（每毫升含19纳居里氚），持续25天。收集尿液和牛奶样本并分析其中的氚含量。大约18天后，乳中的水分、乳脂肪、乳糖和酪蛋白达到平稳水平。乳中水分和尿液中氚的浓度约为饮用水中氚浓度的82%，这表明食物中的水分和代谢过程导致了稀释，以及通过肺部和皮肤进行的交换。在稳定状态下，按重量计算，乳脂肪、乳糖和酪蛋白中的氚活度约为饮用水中氚活度的30%、28%和15%；此时，在这两头奶牛中，每日摄入的氚约有1.5%出现在一升牛奶中。将各种乳成分的比活度与身体水分的比活度进行比较表明，氚掺入量最高的是乳糖（0.58），其次是乳脂肪（0.36）和酪蛋白（0.27）。如文献报道，连续摄入THO后，乳干物质中的氚掺入量（0.45）远高于几种哺乳动物的大多数组织成分。停止给予THO后，牛奶和尿液中的氚水平迅速下降，所有乳成分中快速成分的半衰期约为4天。在乳中的水分、乳脂肪和酪蛋白中分别发现了半衰期为44天、225天和24天的缓慢成分。
