[01] Saadia R. Tariq, Department of Chemistry, Lahore College for Women University, Lahore, Pakistan. [02] Asma Rashid Tariq, Institute of Chemistry, the University of Punjab, Lahore, Pakistan. [03] Samra Lateef, Department of Chemistry, Lahore College for Women University, Lahore, Pakistan. [04] Farhana Mazhar, Department of Chemistry, Lahore College for Women University, Lahore, Pakistan.

Trace metals are known to trigger many biological reactions. Any imbalance in their levels may cause various thyroid disorders like hyperthyroidism. It is therefore, quite important to study the relationships between trace metals and thyroid hormones to help understand the etiology of disease and search for an appropriate treatment regime. To this effect, the levels of selected trace metals were determined in fifty one patients of hyperthyroidism and their age and gender matched healthy controls by using flame atomic absorption spectrophotometer following wet digestion method and the levels of free T3, T4 and TSH were determined by radioimmunoassay technique available at the laboratories of Jinnah Hospital, Lahore. The study evidenced that all the selected trace metals (Cr, Co, Cd, Fe, Ni) were present at enhanced levels in the blood of patients as compared to healthy controls. These metals may affect the thyroid functions (like conversion of T4 to T3) by disturbing the activity of thyroid peroxidase like enzymes. An increasing trend in the concentration of all the metals except Ni was observed with age. Correlation study evidenced Co to be significantly positively correlated with TSH. Gender based studies revealed higher mean values of metals in male patients than in female patients. The exposure of individuals to various metals may lead to the enhanced levels of these metals in the blood. These metals being catalysts for many biological reactions may cause imbalance in thyroid hormones, leading to thyroid dysfunction.

Hyperthyroidism, Metals, T4, Thyroid Stimulating Hormone, Triiodothyronine

[01] Virtanen J.K., Rissanen T.H., Voutilainen S., Tuomainen T.P. Mercury as a risk factor for cardiovascular diseases. J Nut Biochem. 2007; (18): 75-85. [02] Whitnall M., Richardson D.R. Iron: A. New Target for Pharmacological Intervention in Neurodegenerative Diseases. Seminars in Pediatric Neurology. 2006; (13):186-197. [03] Andreali T.E., Carpenter C.C.1., Bannet 1.C., Cecil P.F., Textbook of Medicine, 4th Edition. Philadelphia: W.B. Saunder & Co; 1997; p. 952–3. [04] Ahmed O. M., El-Gareib A.W., Bakery A., Abd Al Tawab S. M., Ahmed A., Thyroid hormones states and brain development interactions. Int J Dev Neurosci, 2007; 26(2): 147-209. [05] Pearce EN, Braverman LE. Environmental pollutants and the thyroid. Best Pract Res Clin Endocrinol Metab.2009; 23(6): 801–813. [06] Beckett G.J., Arthur J.R. Selenium and endocrine systems. J Endocrinol. 2005; (184): 455–65. [07] Thomson A.M., Rogers J.T., Leedman P.J., Review, Iron-regulatory proteins, iron- responsive elements and ferritin mRNA translation. The Intl J. Biochem. & Cell Biol. 1999; 31: 1139-1152. [08] Adair B.M., Cobb G.P. Improved preparation of small biological samples for mercury analysis using cold vapor atomic absorption spectroscopy. Chemosphere. 1999; (38): 2951-2958. [09] Błażewicz A., Dolliver W., Sivsammye S., Deol A., Randhawa R., Orlicz-Szczęsna G., Błażewicz R. Determination of Cd, Co, Cu, Fe, Mn and Zn in thyroid glands of patients with diagnosed nodular goiter using ion chromatography. J Chromat B. 2010; (878): 34-38. [10] Li Q.R., Liao R.Q., Su S.H., Huang S.H., Pan R.H., Huang J.L., Effect of Pb on thyroid function of occupationally exposed workers. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 2003; (212): 111-3. [11] Bigazzi P.E., Autoimmunity and heavy metals, Lupus, 1994; 3(6): 449-53. [12] Osius N., Karmaus W., Kruse H., Witten I., Exposure to polychlorinated biphenyls and levels of thyroid hormones in children. Environ Health Perspect. 1999; 107(10): 843-849. [13] Chen A., Kim S.S., Chung E., Dietrich K.N., Thyroid hormones in relation to lead, mercury and cadmium exposures in the national health and nutrition survey, 2007-2008, Environ Health Perspect. 2013; 121(2): 181–186. [14] Hammouda F., Messaoudi I., El-Hani J., Baati T., Saïd K., Kerkeni A., Reversal of cadmium-induced thyroid dysfunction by selenium, zinc, or their combination in rat. Biol Trace Elem Res. 2008; 126(1-3): 194-203. [15] Abdelouahab, N.; Mergler, D.; Takser, L.; Vanier, C.; St-Jean, M.; Baldwin, M.; Spear, P.A.; Chan, H.M. Gender differences in the effects of organochlorines, mercury, and lead on thyroid hormone levels in lakeside communities of Quebec (Canada) Environ Res. 2008; 107(3): 380-392. [16] Liang Q.R., Liao R.Q., Su S.H., Huang S.H., Pan R.H., Huang J.L., Effects of lead on thyroid function of occupationally exposed workers. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi. 2003; 21(2):111-3. [17] Bledsoe M. L., Pinkerton L. E., Silver S., Deddens J. A. and Biagini R. E., Thyroxine and Free Thyroxine Levels in Workers Occupationally Exposed to Inorganic Lead, Environ Health Insights. 2011; 5 55–61. [18] Gallagher, C.M. and Meliker J.R., Mercury and thyroid autoantibodies in U.S. women, NHANES 2007-2008. Environ. Intl. 2012; 40: 39-43. [19] Soldin O.P., O'Mara D.M., Aschner M. Thyroid hormones and methylmercury toxicity. Biol Trace Elem Res. 2008; 126(1-3):1-12. [20] Ciarrocca M., Tomei F., Caciari T., Cetica C., Andrè J.C., Fiaschetti M., Schifano M.P., Scala B., Scimitto L., Tomei G., Sancini A., Exposure to arsenic in urban and rural areas and effects on thyroid hormones Inhal Toxicol. 2012; 24(9):589-98. [21] Davey J. C., Nomikos A. P., Wungjiranirun M., Sherman J. R., Ingram L., Batki C., Lariviere J. P., Hamilton J. W., Environ Health Perspect. 2008; 116(2): 165–172. [22] Kazi T.G., Afridi H.I., Kazi N., Jamali M.K., Arain M.B., Sarfraz R.A. et al., Distribution of Zn, Cu & Fe in biological samples of Pakistani myocardial infarction (1st, 2nd and 3rd heart attack) patients and controls. Clinic Chim Acta. 2008; (389): 114-119. [23] Kim K.M. Hair Fe and other mineral levels in breast cancer patients. Biol. Trace Elem Res. 2009; (129): 28–35. [24] Parizadeh S.M., Moohebati M., Ghafoori M.F. Ghayour-Mobarhan M., Kazemi-Bajestani S.M., Tavallaie S. Serum selenium and glutathione peroxidase concentrations in Iranian patients with angiography-defined coronary artery disease. Angiology. 2009; (60): 186–191. [25] Sayre L.M., Moreira P.I., Smith M.A., Perry G. Ions and oxidative protein modification in neurological disease. Ann Ist Super Sanita. 2005; (41): 143–164. [26] Yuan X.M., Li W. Iron involvement in multiple signaling pathways of atherosclerosis: a revisited hypothesis. Curr Med Chem. 2008; (15): 2157–2172. [27] Holland N.T., Smith M.T., Eskenazi B. Biological sample collection and processing for molecular epidemiological studies. Mutat Res. 2003; (543): 217–3. [28] Sadat A.F.M. N., Hussain M. I., Serum Trace Elements and Immunoglobin Profile in lung cancer patients. J Appl Res. 2008; (8): 24-33. [29] Caporaso N., Vaught J. Collection, processing, and analysis of preneoplastic specimens. In: Franco EL, Rohan TE, editors. Cancer precursors: epidemiology, detection, and prevention. New York: Springer-Verlag 2002; 33–45. [30] Sansoni B., Panday V.K., Sample treatment of human biological materials, In: Herber RFM, Stoeppler M., editors, Trace element Analysis in biological samples. Amsterdam; Elsevier Sciences 1994; p. 21-52. [31] Alonso M.L., Montana F.P., Miranda M., Castillo C., Hernandez T., Bendito J.C., Interactions between toxic (As, Cd, Hg and Pb) and nutritional essential (Ca, Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Zn) elements in the tissues of cattle from NW Spain. Bio Metals. 2004; (17): 389-397. [32] Shashi A., Kaur V., Sharma N. Thyroid disorders: Prevalence and clinical relevance, Asian J Microbiol, Biotech & Environ Sci. 2009; (11): 819-824. [33] Beard J.L., Green W., Miller L., Finch C., Effects of iron deficiency anemia on hormone levels and thermoregulation during acute cold exposure. Am J Physiol. 1984; (247): R114-R119. [34] Glusker J.P., Katz A.K., Bock C.W. Metal ions in biological systems, Rigaku J. 1999; (16): 8-17. [35] Silva J.J.R.F.D., Williams R.J.P. The Biological Chemistry of the Elements, Clarendon Press: Oxford. 1991. [36] Ahmed Z., Khan M.A., Haq A. Effect of race, gender and age on thyroid and thyroid stimulating hormone levels in NWFP, Pakistan. J Ayub Med Coll Abbottabad. 2009; (21): 21-24. [37] Rodionov D.A., Vitreschak A.G., Mironov A.A., Gelfand M. S., Comparative Genomics of the Vitamin B12 Metabolism and Regulation in Prokaryotes. J Biol Chem. 2003; (27842): 41148-41159. [38] Cammack R., Nickel in metalloproteins. Ads Inorg Chem. 1988; (32), 297-333. [39] Muslim S., Khalil Z. Effect of Age, Sex, Salt, Water and Climate on T3, T4 and TSH in Healthy Individuals, Deptt Zool Peshawar University 2000. [40] Nissinen A., Kivelä S.L., Pekkanen J., et al., Thyroid function tests in elderly Finnish men. Acta Med Scand 1986; 220: 63–9. [41] Dundar B., Oktem F., Arslan M.K., Delibas N., Baykal B., Arslan C., et al., The effect of long-term low-dose lead exposure on thyroid function in adolescents. Environ Res 2006; (101): 140-145. [42] Hasan H. G., J. Mahmood T., Ismael P. A., Studies on the Relationship Between Chromium(III) ion and Thyroid Peroxidase Activity in Seran of Patients with Thyroid Dysfunction, Ibn Al - Haitham J. For Pure & Appl. Sci. 2011. 24 (2). [43] Sack J., Bar-On Z., Shemesh J., Becker R. Serum T4, T3 and TBG concentrations during puberty in males. Eur J Pediatr. 1982; (138): 136–7. [44] Ertek S., Cicero A. F. G., Caglar O., Erdogan G., Relationship between serum zinc levels, thyroid hormones and thyroid volume following successful iodine supplementation, Hormones, 2010, 9(3): 263-268.