Tissue Distribution, Elimination, and Metabolism of Sodium [36Cl]Perchlorate in Lactating Goats
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- 作者：David J. Smith ; Heldur Hakk ; Gerald L. Larsen
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2006
- 出版时间：November 15, 2006
- 年：2006
- 卷：54
- 期：23
- 页码：8829 - 8835
- 全文大小：125K
- 年卷期：v.54,no.23(November 15, 2006)
- ISSN：1520-5118
文摘
Perchlorate has contaminated water sources throughout the United States but particularly in the aridSouthwest, an area containing large numbers of people and few water sources. Recent studies havedemonstrated that perchlorate is present in alfalfa and that perchlorate is secreted into the milk ofcows. Studies in lactating cows have indicated that only a small portion of a perchlorate dose couldbe accounted for by elimination in milk, feces, or urine. It was hypothesized that the remainder of theperchlorate dose was excreted as chloride ion. The purpose of this study was to determine the fateand disposition of 36Cl-perchlorate in lactating dairy goats. Two goats (60 kg) were each orallyadministered 3.5 mg (16.5 
Ci) of 36Cl-perchlorate, a dose selected to approximate environmentalperchlorate exposure but that would allow for adequate detection of radioactive residues after a 72h withdrawal period. Blood, milk, urine, and feces were collected incrementally until slaughter at 72h. Total radioactive residue (TRR) and perchlorate concentrations were measured using radiochemicaltechniques and liquid chromatography mass spectrometry (LC-MS-MS). Peak blood levels of TRRoccurred at 12 h (~195 ppb) postdose; peak levels of parent perchlorate, however, occurred afteronly 2 h, suggesting that perchlorate metabolism occurred rapidly in the rumen. The serum half-lifeof perchlorate was estimated to be 2.3 h. After 24 h, perchlorate was not detectable in blood serumbut TRR remained elevated (160 ppb) through 72 h. Milk perchlorate levels peaked at 12 h (155ppb) and were no longer detectable by 36 h, even though TRRs were readily detected through 72 h.Perchlorate was not detectable in skeletal muscle or liver at slaughter (72 h). Chlorite and chloratewere not detected in any matrix. The only radioactive residues observed were perchlorate and chlorideion. Bioavailability of perchlorate was poor in lactating goats, but the perchlorate that was absorbedintact was rapidly eliminated in milk and urine.
Ci) of 36Cl-perchlorate, a dose selected to approximate environmentalperchlorate exposure but that would allow for adequate detection of radioactive residues after a 72h withdrawal period. Blood, milk, urine, and feces were collected incrementally until slaughter at 72h. Total radioactive residue (TRR) and perchlorate concentrations were measured using radiochemicaltechniques and liquid chromatography mass spectrometry (LC-MS-MS). Peak blood levels of TRRoccurred at 12 h (~195 ppb) postdose; peak levels of parent perchlorate, however, occurred afteronly 2 h, suggesting that perchlorate metabolism occurred rapidly in the rumen. The serum half-lifeof perchlorate was estimated to be 2.3 h. After 24 h, perchlorate was not detectable in blood serumbut TRR remained elevated (160 ppb) through 72 h. Milk perchlorate levels peaked at 12 h (155ppb) and were no longer detectable by 36 h, even though TRRs were readily detected through 72 h.Perchlorate was not detectable in skeletal muscle or liver at slaughter (72 h). Chlorite and chloratewere not detected in any matrix. The only radioactive residues observed were perchlorate and chlorideion. Bioavailability of perchlorate was poor in lactating goats, but the perchlorate that was absorbedintact was rapidly eliminated in milk and urine.