Reis A F, Miranda W L, Chacra A R
Departamento de Medicina, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brasil.
Braz J Med Biol Res. 1998 Dec;31(12):1545-51. doi: 10.1590/s0100-879x1998001200006.
Low levels of sex hormone-binding globulin (SHBG) are considered to be an indirect index of hyperinsulinemia, predicting the later onset of diabetes mellitus type 2. In the insulin resistance state and in the presence of an increased pancreatic beta-cell demand (e.g. obesity) both absolute and relative increases in proinsulin secretion occur. In the present study we investigated the correlation between SHBG and pancreatic beta-cell secretion in men with different body compositions. Eighteen young men (30.0 +/- 2.4 years) with normal glucose tolerance and body mass indexes (BMI) ranging from 22.6 to 43.2 kg/m2 were submitted to an oral glucose tolerance test (75 g) and baseline and 120-min blood samples were used to determine insulin, proinsulin and C-peptide by specific immunoassays. Baseline SHBG values were significantly correlated with baseline insulin (r = -0.58, P < 0.05), proinsulin (r = -0.47, P < 0.05), C-peptide (r = -0.55, P < 0.05) and also with proinsulin at 120 min after glucose load (r = -0.58, P < 0.05). Stepwise regression analysis revealed that proinsulin values at 120 min were the strongest predictor of SHBG (r = -0.58, P < 0.05). When subjects were divided into obese (BMI > 28 kg/m2, N = 8) and nonobese (BMI < or = 25 kg/m2, N = 10) groups, significantly lower levels of SHBG were found in the obese subjects. The obese group had significantly higher baseline proinsulin, C-peptide and 120-min proinsulin and insulin levels. For the first time using a specific assay for insulin determination, a strong inverse correlation between insulinemia and SHBG levels was confirmed. The finding of a strong negative correlation between SHBG levels and pancreatic beta-cell secretion, mainly for the 120-min post-glucose load proinsulin levels, reinforces the concept that low SHBG levels are a suitable marker of increased pancreatic beta-cell demand.
低水平的性激素结合球蛋白（SHBG）被认为是高胰岛素血症的一个间接指标，可预测2型糖尿病的后期发病。在胰岛素抵抗状态以及胰腺β细胞需求增加（如肥胖）的情况下，胰岛素原分泌会出现绝对和相对增加。在本研究中，我们调查了不同身体组成的男性中SHBG与胰腺β细胞分泌之间的相关性。18名糖耐量正常、体重指数（BMI）在22.6至43.2kg/m²之间的年轻男性（30.0±2.4岁）接受了口服葡萄糖耐量试验（75g），并采集了基线和120分钟时的血样，通过特异性免疫测定法测定胰岛素、胰岛素原和C肽。基线SHBG值与基线胰岛素（r = -0.58，P < 0.05）、胰岛素原（r = -0.47，P < 0.05）、C肽（r = -0.55，P < 0.05）以及葡萄糖负荷后120分钟时的胰岛素原（r = -0.58，P < 0.05）均显著相关。逐步回归分析显示，120分钟时的胰岛素原值是SHBG的最强预测指标（r = -0.58，P < 0.05）。当受试者分为肥胖组（BMI > 28kg/m²，N = 8）和非肥胖组（BMI≤25kg/m²，N = 10）时，肥胖受试者的SHBG水平显著较低。肥胖组的基线胰岛素原、C肽以及120分钟时的胰岛素原和胰岛素水平显著更高。首次使用特异性胰岛素测定法，证实了胰岛素血症与SHBG水平之间存在强烈的负相关。SHBG水平与胰腺β细胞分泌之间存在强烈的负相关这一发现，主要是针对葡萄糖负荷后120分钟时的胰岛素原水平，强化了低SHBG水平是胰腺β细胞需求增加的合适标志物这一概念。
