Dr. Ron’s Research Review – September 17, 2014

© 2014

This week’s research review focuses on zinc, copper, selenium and thyroid function.

Zinc and Copper

A study analyzed data from National Health and Nutrition Examination Survey for the cycle 2011-2012.
For males, zinc levels were associated with decreased levels of free and total T4, and copper was associated with increased levels of free and total T4. Among females, levels of copper were associated with increased levels of total T3 and T4.
Smoking was associated with lower TSH and zinc and higher TGN and copper in males and lower total T4 in females. Also, males had about 5-10 percent higher levels of both selenium and zinc, but as much as 20 percent lower levels of copper than females. Serum zinc and copper are associated with thyroid function and influenced by smoking status. (Jain, 2014)

Selenium and Copper

Thyroid hormone action is mediated by the thyroid hormone receptors TRalpha1 and TRbeta. Defects in TRbeta lead to RTH (resistance to thyroid hormone) beta, a syndrome characterized by high levels of thyroid hormone and non-suppressed TSH (thyroid-stimulating hormone). However, a correct diagnosis of RTHbeta patients is difficult as the clinical picture varies.
The ratio of serum copper and selenium, which is largely independent of thyroid hormone levels, volume changes or sample degradation, can constitute a valuable novel biomarker for RTHbeta. Moreover, it could also provide a suitable large-scale screening parameter to identify RTHalpha patients, which have not been identified to date. (Mittag et al., 2012)

Dr. Ron


 

Articles

Thyroid function and serum copper, selenium, and zinc in general U.S. population.
            (Jain, 2014) Download
Association of the levels of serum selenium (Se), zinc (Zn), and copper (Cu) with thyroid function was assessed by analyzing data from National Health and Nutrition Examination Survey for the cycle 2011-2012. Thyroid function variables analyzed were as follows: thyroid-stimulating hormone (TSH), free and total triiodothyronine (FT3, TT3), free and total thyroxine (FT4, TT4), and thyroglobulin (TGN). Regression models with log-transformed values of thyroid hormones as independent variables and age, race/ethnicity, smoking and iodine sufficiency status, respondents' education, and levels of Se, Zn, and Cu as dependent variables were fitted. For males, levels of Zn were associated with decreased levels of FT4 and TT4, and levels of Cu were associated with increased levels of FT4 and TT4. For females, levels of Cu were associated with increased levels of TT3 and TT4. Smoking was found to be associated with lower levels of TSH and higher levels of TGN in males. Smoking was found to be associated with lower levels of TT4 in females. Males had about 5-10% higher levels of both Se and Zn, but as much as 20% lower levels of Cu than females. Smoking was associated with lower levels of Zn, but higher levels of Cu in males.

Serum copper as a novel biomarker for resistance to thyroid hormone.
            (Mittag et al., 2012) Download
Thyroid hormone action is mediated by the thyroid hormone receptors TRalpha1 and TRbeta. Defects in TRbeta lead to RTH (resistance to thyroid hormone) beta, a syndrome characterized by high levels of thyroid hormone and non-suppressed TSH (thyroid-stimulating hormone). However, a correct diagnosis of RTHbeta patients is difficult as the clinical picture varies. A biochemical serum marker indicative of defects in TRbeta signalling is needed and could simplify the diagnosis of RTHbeta, in particular the differentiation to TSH-secreting pituitary adenomas, which present with clinically similar symptoms. In the present paper we show that serum copper levels are regulated by thyroid hormone, which stimulates the synthesis and the export of the hepatic copper-transport protein ceruloplasmin into the serum. This is accompanied by a concerted reduction in the mRNA levels of other copper-containing proteins such as metallothioneins 1 and 2 or superoxide dismutase 1. The induction of serum copper is abolished in genetically hyperthyroid mice lacking TRbeta and human RTHbeta patients, demonstrating an important role of TRbeta for this process. Together with a previously reported TRalpha1 specific regulation of serum selenium, we show that the ratio of serum copper and selenium, which is largely independent of thyroid hormone levels, volume changes or sample degradation, can constitute a valuable novel biomarker for RTHbeta. Moreover, it could also provide a suitable large-scale screening parameter to identify RTHalpha patients, which have not been identified to date.

 

References

Jain, RB (2014), ‘Thyroid function and serum copper, selenium, and zinc in general U.S. population.’, Biol Trace Elem Res, 159 (1-3), 87-98. PubMedID: 24789479
Mittag, J, et al. (2012), ‘Serum copper as a novel biomarker for resistance to thyroid hormone.’, Biochem J, 443 (1), 103-9. PubMedID: 22220593