Oliveira M C, Pizarro C B, Cassal A, Cremonese R, Vieira J G
Departamento de Endocrinologia, Fundação Faculdade Federal de Ciências Médicas de Porto Alegre, RS, Brasil.
Braz J Med Biol Res. 1999 Jan;32(1):73-7. doi: 10.1590/s0100-879x1999000100011.
Secretion of the alpha-subunit of pituitary glycoprotein hormones usually follows the secretion of intact gonadotropins and is increased in gonadal failure and decreased in isolated gonadotropin deficiency. The aim of the present study was to determine the levels of the alpha-subunit in the serum of patients with cirrhosis of the liver and to compare the results obtained for eugonadal cirrhotic patients with those obtained for cirrhotic patients with hypogonadotropic hypogonadism. Forty-seven of 63 patients with cirrhosis (74.6%) presented hypogonadism (which was central in 45 cases and primary in 2), 7 were eugonadal, and 9 women were in normal menopause. The serum alpha-subunit was measured by the fluorimetric method using monoclonal antibodies. Cross-reactivity with LH, TSH, FSH and hCG was 6.5, 1.2, 4.3 and 1.1%, respectively, with an intra-assay coefficient of variation (CV) of less than 5% and an interassay CV of 5%, and sensitivity limit of 4 ng/l. The serum alpha-subunit concentration ranged from 36 to 6253 ng/l, with a median of 273 ng/l. The median was 251 ng/l for patients with central hypogonadism and 198 ng/l for eugonadal patients. The correlation between the alpha-subunit and basal LH levels was significant both in the total sample (r = 0.48, P < 0.01) and in the cirrhotic patients with central hypogonadism (r = 0.33, P = 0.02). Among men with central hypogonadism there was a negative correlation between alpha-subunit levels and total testosterone levels (r = -0.54, P < 0.01) as well as free testosterone levels (r = -0.53, P < 0.01). In conclusion, although the alpha-subunit levels are correlated with LH levels, at present they cannot be used as markers for hypogonadism in patients with cirrhosis of the liver.
垂体糖蛋白激素α亚基的分泌通常伴随完整促性腺激素的分泌，在性腺功能衰竭时升高，在孤立性促性腺激素缺乏时降低。本研究的目的是测定肝硬化患者血清中α亚基的水平，并将性腺功能正常的肝硬化患者的结果与性腺功能减退性性腺功能减退的肝硬化患者的结果进行比较。63例肝硬化患者中有47例（74.6%）出现性腺功能减退（其中45例为中枢性，2例为原发性），7例性腺功能正常，9例女性处于正常绝经状态。采用单克隆抗体荧光法测定血清α亚基。与LH、TSH、FSH和hCG的交叉反应率分别为6.5%、1.2%、4.3%和1.1%，批内变异系数（CV）小于5%，批间CV为5%，灵敏度极限为4 ng/l。血清α亚基浓度范围为36至6253 ng/l，中位数为273 ng/l。中枢性性腺功能减退患者的中位数为251 ng/l，性腺功能正常患者的中位数为198 ng/l。在整个样本中（r = 0.48，P < 0.01）以及中枢性性腺功能减退的肝硬化患者中（r = 0.33，P = 0.02），α亚基与基础LH水平之间的相关性均显著。在中枢性性腺功能减退的男性中，α亚基水平与总睾酮水平（r = -0.54，P < 0.01）以及游离睾酮水平（r = -0.53，P < 0.01）之间存在负相关。总之，虽然α亚基水平与LH水平相关，但目前它们不能用作肝硬化患者性腺功能减退的标志物。
