The thyroid gland is, without a doubt, one of the most highly influential glands in the human body. As our Chief Medical Officer, Dr. R.W. “Chip” Watkins, MD, MPH, FAAFP, likes to say: nothing moves in the body without the thyroid.
Thyroid Hormones and SHBG
Thyroid hormones are important for the catabolism and anabolism of many molecules. Thyroid hormones seem to dictate the production of an important glycoprotein called Sex Hormone Binding Globulin, or SHBG. There is positive correlation between thyroid hormone levels and SHBG levels.
SHBG and Hypothyroidism
One study found that those with hypothyroidism had lower levels of SHBG than subjects with healthy thyroid glands. After the researchers of this study administered thyroid medication to the hypothyroid subjects, they found that their SHBG levels increased in a dose-dependent manner (1).
SHBG and Hyperthyroidism
Another study found high SHBG levels to be associated with hyperthyroidism. This study saw a decrease in SHBG levels after normalizing thyroid hormone levels in hyperthyroid subjects (2).
SHBG’s production occurs in the liver and is regulated by hepatocyte nuclear factor-4-alpha or HNF4A. Thyroid hormones’ ability to raise SHBG levels is proposed to be through increasing HNF4A gene expression, thus indirectly upregulating SHBG levels (3).
High SHBG levels can have some negative implications.
One major negative implication of high SHBG could be a decrease in the level of free, unbound sex hormones circulating in the bloodstream. One study found that male subjects with normal total testosterone levels and low calculated free testosterone had high levels of SHBG (4). Thus, one could possibly draw the connection between high SHBG levels and symptoms of hypogonadism in males, such as low libido and fatigue.
Hypogonadism symptoms and low free estradiol may be present in females with high SHBG, as estradiol also binds to SHBG.
Testing Thyroid Function and SHBG Levels
It is important to assess thyroid hormone and SHBG levels to determine if there is an imbalance. If your SHBG level is elevated, boron supplementation may be helpful in reducing it (5).
In addition to assessing thyroid and sex hormone status, your neurotransmitter and adrenal hormone levels may need to be measured. Thyroid hormones, sex hormones, neurotransmitters, and adrenal hormones all function together to create optimal health and balance throughout the body.
Talk to your health care practitioner today about Sanesco’s testing to gain further insight into your specific biochemistry and hormonal balance.
- Cavaliere, H., Abelin, N., & Medeiros-Neto, G. (1988). Serum Levels of Total Testosterone and Sex Hormone Binding Globulin in Hypothyroid Patients and Normal Subjects Treated with Incremental Doses of L-T 4 or L-T 3. Journal of Andrology, 9(3), 215-219. doi:10.1002/j.1939-4640.1988.tb01038.x
- Ford, H. C., Cooke, R. R., Kelghtley, E. A., & Feek, C. M. (1992). Serum levels of free and bound testosterone in hyperthyroidism. Clin Endocrinol Clinical Endocrinology, 36(2), 187-192. doi:10.1111/j.1365-2265.1992.tb00956.x
- Selva, D. M., & Hammond, G. L. (2009). Thyroid hormones act indirectly to increase sex hormone-binding globulin production by liver via hepatocyte nuclear factor-4-alpha. Journal of Molecular Endocrinology, 43(1), 19-27. doi:10.1677/jme-09-0025
- Antonio, L., Wu, F. C., O’neill, T. W., Pye, S. R., Ahern, T. B., Laurent, M. R., . . . Vanderschueren, D. (2016). Low Free Testosterone Is Associated with Hypogonadal Signs and Symptoms in Men with Normal Total Testosterone. The Journal of Clinical Endocrinology & Metabolism, 101(7), 2647-2657. doi:10.1210/jc.2015-4106
- Naghii, M. R., Mofid, M., Asgari, A. R., Hedayati, M., & Daneshpour, M. (2011). Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines. Journal of Trace Elements in Medicine and Biology, 25(1), 54-58. doi:10.1016/j.jtemb.2010.10.001