Changes of sex hormones and sex hormone-binding globulin levels in male adults with hyperthyroidism before and after antithyroid drug treatment

Abstract

Objective: To observe the changes of sex hormone and sex hormone-binding globulin (SHBG) levels in young male patients with hyperthyroidism before and after antithyroid drug (ATD) treatment. Methods: Between January 2015 and July 2016, forty male patients with hyperthyroidism aged 19-52 years (with an median age of 33.1 years) were enrolled in the Department of Endocrinology of Peking Union Medical College Hospital. Blood samples were taken before treatment and at 1 month, 2 months, 3 months and 5 months after treatment to evaluate thyroid function, follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone(T), free testosterone(FT), estradiol(E2), prolactin and SHBG. Results: A total of 40 patients were enrolled but only 35 patients completed the follow-up. The patients had high levels of thyroid function, SHBG and sex hormones before treatment. Before treatment, free thyroxine (FT(4)), free triiodothyronine (FT(3)), SHBG, LH, estradiol, testosterone and free testosterone was (0.30±0.12) pmol/L, (9.68±4.73) pmol/L, (146±111) nmol/L, (8.41±3.61) U/L, (19.9±7.7) pmol/L, (29.9±9.5) nmol/L and (0.24±0.08) nmol/L, respectively. After treatment, the level of triiodothyronine, thyroxine, FT(3) and FT(4) gradually decreased to normal (all P<0.001). Thyroid stimulating hormone (TSH) gradually increased to normal (P<0.001). LH and estradiol levels gradually decreased (all P<0.001). FSH decreased but the difference was not statistically significant. Prolactin did not change significantly. Testosterone and SHBG levels decreased significantly while the levels of free testosterone, free testosterone percentage (FT%), bio-available testosterone (BAT), bio-available testosterone percentage (BAT%), free androgen index (FAI) gradually increased and stabilized (all P<0.001). The difference was not statistically significant between T/LH and E2/LH before and after treatment (all P>0.05). However FT/LH gradually increased and its difference was statistically significant (P<0.001). Conclusion: The levels of LH, estradiol, testosterone and SHBG in male patients with hyperthyroidism significantly increased, while the free testosterone level decreased, but they all gradually returned to normal with the lowering of thyroid hormone levels during ATD treatment.