Kumar A, Mohanty B P, Rani L
Department of Reproductive Biology, All India Institute of Medical Sciences, New Delhi, India.
Andrologia. 2007 Dec;39(6):253-60. doi: 10.1111/j.1439-0272.2007.00798.x.
Inconsistent alterations in gonadal steroidogenesis and pituitary functions have been reported in hypothyroid males. We have compared the lipid and endocrine profiles of the euthyroid and hypothyroid [thyroid-stimulating hormone (TSH) >100 mIU l(-1)] males. Hypothyroidism was found to be associated with an increase in the circulating level of total cholesterol and LDL-cholesterol (LDL-C) and a reduction in the levels of progesterone and testosterone, without any change in the serum levels of oestradiol and gonadotrophins. The failure of gonadotrophins to rise could be accounted by a normal level of serum oestradiol in the hypothyroid male. A mild hyperprolactinaemia was also noted in the hypothyroid patients. The reduction in serum testosterone level could be explained by (i) a reduced uptake of LDL-C by the Leydig cells and thereby a reduction in the synthesis of progesterone and consequentially testosterone, (ii) a further reduction in the rate of conversion of progesterone to testosterone, (iii) a higher rate of conversion of testosterone to oestradiol, (iv) a decrease in serum triiodothyronine and (v) hyperprolactinaemia. Rise in TSH needs to be investigated as a cause of the suppression of gonadal steroidogenesis.
据报道，甲状腺功能减退的男性性腺类固醇生成和垂体功能存在不一致的改变。我们比较了甲状腺功能正常和甲状腺功能减退（促甲状腺激素[TSH]>100 mIU l(-1)）男性的脂质和内分泌谱。发现甲状腺功能减退与总胆固醇和低密度脂蛋白胆固醇（LDL-C）循环水平升高以及孕酮和睾酮水平降低有关，而雌二醇和促性腺激素的血清水平没有任何变化。甲状腺功能减退男性血清雌二醇水平正常可以解释促性腺激素未能升高的原因。甲状腺功能减退患者还出现了轻度高泌乳素血症。血清睾酮水平降低的原因可能是：（i）睾丸间质细胞对LDL-C的摄取减少，从而导致孕酮合成减少，进而睾酮合成减少；（ii）孕酮向睾酮转化的速率进一步降低；（iii）睾酮向雌二醇转化的速率更高；（iv）血清三碘甲状腺原氨酸减少；（v）高泌乳素血症。TSH升高作为性腺类固醇生成受抑制的原因需要进行研究。
