Impact of Thyroid Abnormalities on Male Fertility 甲状腺功能异常对男性生育力的影响

Normal thyroid function is imperative to maintain normal male fertility. Hyper-and hypothyroidism can result in alterations in sex hormone binding globulin (SHBG) and sex steroids and can result in gonadal dysfunction. Alterations in thyroid function appear to affect female fertility more severely compared to male fertility. Thyroid hormones have also been found to play a role in Sertoli and Leydig cell proliferation, testicular maturation and steroidogenesis. 1

正常的甲状腺功能是维持男性正常生育能力的必要条件。甲状腺功能亢进和甲状腺功能减退可导致性激素结合球蛋白 (SHBG) 和性类固醇的改变，并可导致性腺功能障碍。与男性生育能力相比，甲状腺功能的改变似乎对女性生育能力的影响更为严重。据发现，甲状腺激素在支持细胞和间质细胞增殖、睾丸成熟和类固醇生成中也发挥着作用。1

Hyperthyroidism can result in decreased sperm concentration and motility, as well as increased SHBG levels,thereby decreasing bioavailable testosterone levels. Although total testosterone concentration can increase, free testosterone levels were found to remain stable.2 Total and free estradiol levels are also often elevated and may contribute to the development of gynecomastia.3 Despite normal to increased total testosterone and normal free testosterone levels, males with hyperthyroidism can also exhibit symptoms of sexual dysfunction, including hypoactive sexual disorder, erectile dysfunction, premature ejaculation, or delayed ejaculation. 4 Treatment for thyrotoxicosis results in hormonal normalization and improvements in semen parameters and symptoms of sexual dysfunction.

甲状腺功能亢进可导致精子浓度和活力下降，以及 SHBG 水平升高，从而降低睾酮水平的生物活性。虽然总睾酮浓度会增加，但游离睾酮水平保持稳定。2 总雌二醇和游离雌二醇水平也经常升高，并可能导致男性乳房发育。3 尽管总睾酮处于正常至升高区间，游离睾酮水平正常，但患有甲状腺功能亢进症的男性也可能表现出性功能障碍的症状，包括性欲减退、勃起功能障碍、早泄或射精延迟。 4 治疗甲状腺机能亢进会使激素水平正常，改善精液参数和性功能障碍的症状。

Hypothyroidism can cause abnormalities in morphology. Hypothyroidism results in decreased SHBG levels, leading to reduced total testosterone concentration. Free testosterone levels are also reduced in 60% of men with hypothyroidism. Sexual dysfunction is also prevalent with hypothyroidism and can include similar symptoms as described for hyperthyroidism. 4 Like hyperthyroidism, hormonal and seminal aberrations along with sexual dysfunction symptoms have been noted to normalize after initiating thyroid replacement therapy. 5

甲状腺功能减退可导致精液形态异常。甲状腺功能减退导致SHBG 水平降低，进而导致总睾酮浓度降低。60% 的甲状腺功能减退症男性的游离睾酮水平也降低。性功能障碍也普遍存在于甲状腺功能减退症的患者中，他们也可能出现与甲状腺功能亢进患者相似的症状。4与甲状腺功能亢进一样，伴随性功能障碍症状出现的激素和精液异常在开始甲状腺替代治疗后会恢复正常。5

Reference 文献参考：

1.Wajner SM,Wagner MS, Maia AL. Clinical implications of alteredthyroid status in male testicular function. Arq bras EndocrinolMetabol. 2009; 53: 976-82.

2. Ruder H,Corvol P,Mahoudeau JA,et al.Effects of inducedhyperthyroidism on steroid metabolism in man. J Clin EndocrinolMetab. 1971; 33: 382-7

3. Krassas GE, Pontikides N, Deligianni V, Miras K. A prospectivecontrolled study of the impact of hyperthyroidism on reproductivefunction in males. J Clin Endocrinol Metab. 2002; 87: 3667-71.

4. Carani C, Isidori AM, Granata A, et al. Multicenter study on theprevalence of sexual symptoms in male hypo- and hyperthyroidpatients. J Clin Endocrinol Metab. 2005; 90: 6472-9

5.Donnelly P, White C. Testicular dysfunction in men with primaryypothyroidism;reversal of hypogonadotrophic hypogonadism withreplacement thyroxine. Clin Endocrinol. 2000; 52: 197-201