State University of New York at Buffalo,Buffalo, NY, USA.
Diabetes Care. 2011 Aug;34(8):1854-9. doi: 10.2337/dc11-0208. Epub 2011 Jun 29.
It has been suggested that the high prevalence of subnormal free testosterone concentrations, along with low or inappropriately normal gonadotropins in men with type 2 diabetes, may be the result of an increase in plasma estradiol concentrations secondary to an increase in aromatase activity in the adipose tissue that leads to the suppression of the hypothalamo-hypophyseal-gonadal axis.
To investigate this hypothesis, plasma estradiol, testosterone, leutinizing hormone, follicle-stimulating hormone, and sex hormone-binding globulin (SHBG) concentrations were measured in fasting blood samples of 240 men with type 2 diabetes. Free estradiol concentrations were either calculated (n = 198) using total estradiol and SHBG measured by immunoassay or directly measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) and equilibrium dialysis (n = 102).
The calculated free estradiol concentration in men with subnormal free testosterone concentrations was lower than that in men with normal free testosterone concentrations (median 0.047 vs. 0.063 ng/dL, P < 0.001). Directly measured (LC-MS/MS) free estradiol concentrations were also lower in men with subnormal free testosterone concentrations (median 0.025 vs. 0.045 ng/dL, P = 0.008). Free estradiol concentrations were directly related to free testosterone but not to BMI or age.
These data show that the suppression of the hypothalamo-hypophyseal-gonadal axis in patients with subnormal free testosterone concentrations and type 2 diabetes is not associated with increased estradiol concentrations. The pathogenesis of subnormal free testosterone concentrations in type 2 diabetes needs to be investigated further.
有研究表明，2 型糖尿病男性游离睾酮浓度偏低或正常低值，同时伴有雌二醇浓度升高和促性腺激素水平降低，这可能是由于脂肪组织中芳香化酶活性增加，导致血浆雌二醇浓度升高，从而抑制了下丘脑-垂体-性腺轴。
为了验证这一假说，我们检测了 240 例 2 型糖尿病男性空腹血样中的雌二醇、睾酮、促黄体生成素、促卵泡生成素和性激素结合球蛋白（SHBG）浓度。游离雌二醇浓度通过免疫测定法检测总雌二醇和 SHBG 计算得出（n = 198），或通过液相色谱串联质谱法（LC-MS/MS）和平衡透析直接测量（n = 102）。
游离睾酮浓度偏低的男性，其计算得出的游离雌二醇浓度要低于游离睾酮浓度正常的男性（中位数分别为 0.047 和 0.063ng/dL，P＜0.001）。通过 LC-MS/MS 直接测量的游离雌二醇浓度在游离睾酮浓度偏低的男性中也较低（中位数分别为 0.025 和 0.045ng/dL，P=0.008）。游离雌二醇浓度与游离睾酮直接相关，但与 BMI 或年龄无关。
这些数据表明，2 型糖尿病患者游离睾酮浓度偏低伴下丘脑-垂体-性腺轴抑制与雌二醇浓度升高无关。2 型糖尿病患者游离睾酮浓度偏低的发病机制仍需进一步研究。
