Abstract
Application of a sensitive new detection method has revealed widespread perchlorate contamination of groundwater in the southwestern United States, typically at 0.005-0.020 mg/L (5-20 ppb). Perchlorate is a competitive inhibitor of the process by which iodide is actively transported from the bloodstream into the thyroid. This inhibitory action of perchlorate is the basis of its pharmaceutical use (in the treatment of hyperthyroidism) as well as its potential toxicity. To establish the dose response in humans for perchlorate inhibition of thyroidal iodide uptake and any short-term effects on thyroid hormones, we gave perchlorate in drinking water at 0.007, 0.02, 0.1, or 0.5 mg/kg-day to 37 male and female volunteers for 14 days. In 24 subjects we performed 8- and 24-hr measurements of thyroidal (123)I uptake (RAIU) before exposure, on exposure days 2 (E2) and 14 (E14), and 15 days postexposure (P15). In another 13 subjects we omitted both E2 studies and the 8-hr P15 study. We observed a strong correlation between the 8- and 24-hr RAIU over all dose groups and measurement days. We found no difference between E2 and E14 in the inhibition of RAIU produced by a given perchlorate dose. We also found no sex difference. On both E2 and E14, the dose response was a negative linear function of the logarithm of dose. Based on the dose response for inhibition of the 8- and 24-hr RAIU on E14 in all subjects, we derived estimates of the true no-effect level: 5.2 and 6.4 micro g/kg-day, respectively. Given default body weight and exposure assumptions, these doses would be ingested by an adult if the drinking-water supply contained perchlorate at concentrations of approximately 180 and 220 micro g/L (ppb), respectively. On P15, RAIU was not significantly different from baseline. In 24 subjects we measured serum levels of thyroxine (total and free), triiodothyronine, and thyrotropin in blood sampled 16 times throughout the study. Only the 0.5 mg/kg-day dose group showed any effect on serum hormones: a slight downward trend in thyrotropin levels in morning blood draws during perchlorate exposure, with recovery by P15.
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- Andersen S., Pedersen K. M., Pedersen I. B., Laurberg P. Variations in urinary iodine excretion and thyroid function. A 1-year study in healthy men. Eur J Endocrinol. 2001 May;144(5):461–465. doi: 10.1530/eje.0.1440461. [DOI] [PubMed] [Google Scholar]
- Bartalena L., Brogioni S., Grasso L., Bogazzi F., Burelli A., Martino E. Treatment of amiodarone-induced thyrotoxicosis, a difficult challenge: results of a prospective study. J Clin Endocrinol Metab. 1996 Aug;81(8):2930–2933. doi: 10.1210/jcem.81.8.8768854. [DOI] [PubMed] [Google Scholar]
- Barzilai D., Sheinfeld M. Fatal complications following use of potassium perchlorate in thyrotoxicosis. Report of two cases and a review of the literature. Isr J Med Sci. 1966 Jul-Aug;2(4):453–456. [PubMed] [Google Scholar]
- Brabant G., Bergmann P., Kirsch C. M., Köhrle J., Hesch R. D., von zur Mühlen A. Early adaptation of thyrotropin and thyroglobulin secretion to experimentally decreased iodine supply in man. Metabolism. 1992 Oct;41(10):1093–1096. doi: 10.1016/0026-0495(92)90291-h. [DOI] [PubMed] [Google Scholar]
- Buchinger W., Lorenz-Wawschinek O., Semlitsch G., Langsteger W., Binter G., Bonelli R. M., Eber O. Thyrotropin and thyroglobulin as an index of optimal iodine intake: correlation with iodine excretion of 39,913 euthyroid patients. Thyroid. 1997 Aug;7(4):593–597. doi: 10.1089/thy.1997.7.593. [DOI] [PubMed] [Google Scholar]
- Carrasco N. Iodide transport in the thyroid gland. Biochim Biophys Acta. 1993 Jun 8;1154(1):65–82. doi: 10.1016/0304-4157(93)90017-i. [DOI] [PubMed] [Google Scholar]
- Connell J. M. Long-term use of potassium perchlorate. Postgrad Med J. 1981 Aug;57(670):516–517. doi: 10.1136/pgmj.57.670.516. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DEGROOT L. J., GREER M. A. The effect of stable iodide on thyroid secretion in man. Metabolism. 1956 Nov;5(6 Pt 1):682–696. [PubMed] [Google Scholar]
- Eskandari S., Loo D. D., Dai G., Levy O., Wright E. M., Carrasco N. Thyroid Na+/I- symporter. Mechanism, stoichiometry, and specificity. J Biol Chem. 1997 Oct 24;272(43):27230–27238. doi: 10.1074/jbc.272.43.27230. [DOI] [PubMed] [Google Scholar]
- Fisher J., Todd P., Mattie D., Godfrey D., Narayanan L., Yu K. Preliminary development of a physiological model for perchlorate in the adult male rat: a framework for further studies. Drug Chem Toxicol. 2000 Feb;23(1):243–258. doi: 10.1081/dct-100100113. [DOI] [PubMed] [Google Scholar]
- Fukuda H., Yasuda N., Greer M. A., Kutas M., Greer S. E. Changes in plasma thyroxine, triiodothyronine, and TSH during adaptation to iodine deficiency in the rat. Endocrinology. 1975 Aug;97(2):307–314. doi: 10.1210/endo-97-2-307. [DOI] [PubMed] [Google Scholar]
- GREER M. A. Correlation of the 24-hour radioiodine uptake of the human thyroid gland with the six- and eight-hour up-takes and the accumulation gradient. J Clin Invest. 1951 Mar;30(3):301–304. doi: 10.1172/JCI102444. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gibbs J. P., Ahmad R., Crump K. S., Houck D. P., Leveille T. S., Findley J. E., Francis M. Evaluation of a population with occupational exposure to airborne ammonium perchlorate for possible acute or chronic effects on thyroid function. J Occup Environ Med. 1998 Dec;40(12):1072–1082. doi: 10.1097/00043764-199812000-00007. [DOI] [PubMed] [Google Scholar]
- Greer M. A., Stott A. K., Milne K. A. Effects of thiocyanate, perchlorate and other anions on thyroidal iodine metabolism. Endocrinology. 1966 Aug;79(2):237–247. doi: 10.1210/endo-79-2-237. [DOI] [PubMed] [Google Scholar]
- Hayes A. A., Akre C. M., Gorman C. A. Iodine-131 treatment of Graves' disease using modified early iodine-131 uptake measurements in therapy dose calculations. J Nucl Med. 1990 Apr;31(4):519–522. [PubMed] [Google Scholar]
- Hollowell J. G., Staehling N. W., Hannon W. H., Flanders D. W., Gunter E. W., Maberly G. F., Braverman L. E., Pino S., Miller D. T., Garbe P. L. Iodine nutrition in the United States. Trends and public health implications: iodine excretion data from National Health and Nutrition Examination Surveys I and III (1971-1974 and 1988-1994) J Clin Endocrinol Metab. 1998 Oct;83(10):3401–3408. doi: 10.1210/jcem.83.10.5168. [DOI] [PubMed] [Google Scholar]
- Lamm S. H., Braverman L. E., Li F. X., Richman K., Pino S., Howearth G. Thyroid health status of ammonium perchlorate workers: a cross-sectional occupational health study. J Occup Environ Med. 1999 Apr;41(4):248–260. doi: 10.1097/00043764-199904000-00006. [DOI] [PubMed] [Google Scholar]
- Lawrence J. E., Lamm S. H., Pino S., Richman K., Braverman L. E. The effect of short-term low-dose perchlorate on various aspects of thyroid function. Thyroid. 2000 Aug;10(8):659–663. doi: 10.1089/10507250050137734. [DOI] [PubMed] [Google Scholar]
- Lawrence J., Lamm S., Braverman L. E. Low dose perchlorate (3 mg daily) and thyroid function. Thyroid. 2001 Mar;11(3):295–295. doi: 10.1089/105072501750159796. [DOI] [PubMed] [Google Scholar]
- Loh K. C. Amiodarone-induced thyroid disorders: a clinical review. Postgrad Med J. 2000 Mar;76(893):133–140. doi: 10.1136/pmj.76.893.133. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moulopoulos D. S., Koutras D. A., Mantzos J., Souvatzoglou A., Piperingos G. D., Karaiskos K. S., Makriyannis D., Sfontouris J., Moulopoulos S. D. The relation of serum T4 and TSH with the urinary iodine excretion. J Endocrinol Invest. 1988 Jun;11(6):437–439. doi: 10.1007/BF03349078. [DOI] [PubMed] [Google Scholar]
- Rasmussen L. B., Ovesen L., Christiansen E. Day-to-day and within-day variation in urinary iodine excretion. Eur J Clin Nutr. 1999 May;53(5):401–407. doi: 10.1038/sj.ejcn.1600762. [DOI] [PubMed] [Google Scholar]
- SOLOMON D. H. Factors affecting the fractional rate of release of radioiodine from the thyroid gland in man. Metabolism. 1956 Nov;5(6 Pt 1):667–681. [PubMed] [Google Scholar]
- STANBURY J. B., WYNGAARDEN J. B. Effect of perchlorate on the human thyroid gland. Metabolism. 1952 Nov;1(6):533–539. [PubMed] [Google Scholar]
- TROTTER W. R. The relative toxicity of antithyroid drugs. J New Drugs. 1962 Nov-Dec;2:333–343. doi: 10.1177/009127006200200603. [DOI] [PubMed] [Google Scholar]
- Thomson C. D., Smith T. E., Butler K. A., Packer M. A. An evaluation of urinary measures of iodine and selenium status. J Trace Elem Med Biol. 1996 Dec;10(4):214–222. doi: 10.1016/S0946-672X(96)80038-1. [DOI] [PubMed] [Google Scholar]
- WYNGAARDEN J. B., WRIGHT B. M., WAYS P. The effect of certain anions upon the accumulation and retention of iodide by the thyroid gland. Endocrinology. 1952 May;50(5):537–549. doi: 10.1210/endo-50-5-537. [DOI] [PubMed] [Google Scholar]
- Wenzel K. W., Lente J. R. Similar effects of thionamide drugs and perchlorate on thyroid-stimulating immunoglobulins in Graves' disease: evidence against an immunosuppressive action of thionamide drugs. J Clin Endocrinol Metab. 1984 Jan;58(1):62–69. doi: 10.1210/jcem-58-1-62. [DOI] [PubMed] [Google Scholar]
- Wolff J. Perchlorate and the thyroid gland. Pharmacol Rev. 1998 Mar;50(1):89–105. [PubMed] [Google Scholar]