Nagi D K, Ali V M, Walji S, Jain S K, Yudkin J S
Department of Medicine, University College London Medical School, U.K.
Diabetes Care. 1996 Jan;19(1):39-42. doi: 10.2337/diacare.19.1.39.
To investigate the contributions of intact proinsulin and of des-31,32-proinsulin to fasting concentrations of insulin-like molecules in nondiabetic subjects from two ethnic groups (Asian and white) and to see whether Asian subjects are hyperinsulinemic compared with white subjects using highly specific assays for insulin.
We investigated subjects with normal glucose tolerance (NGT) (82 Asian and 67 white) and impaired glucose tolerance (IGT) (16 Asian and 13 white), diagnosed by using standard World Health Organization criteria. Highly specific monoclonal antibody-based assays were used to measure insulin, intact proinsulin, and des-31,32-proinsulin. An index of insulin secretion was derived as a ratio of incremental insulin to incremental glucose concentrations from 0 to 30 min during an oral glucose tolerance test.
Asian subjects with NGT, despite being significantly thinner than whites (BMI 24.4 +/- 3.5 vs. 25.7 +/- 3.7 kg/m2, P = 0.04), had a more central distribution of obesity (subscapsular-to-triceps skinfold ratios 1.36 +/- 0.69 vs. 1.17 +/- 0.41, P = 0.047). Asian subjects with NGT showed significant hyperinsulinemia 2 h after oral glucose load (plasma insulin median 274 pmol/l [range 26-1,505] vs. 186 pmol/l [27-720], P < 0.005) compared with whites. Asian subjects with NGT also had significantly higher insulin increments (P < 0.02) compared with white subjects and significantly higher fasting concentrations of intact proinsulin (median 2.7 pmol/l [range 0.9-14.1] vs. 2.1 [0.8-7.9], P < 0.02) but not of des-31,32-proinsulin. The ratio of proinsulin-like molecules to the total sum of three insulin-like molecules, however, was similar between Asian and white subjects with NGT and IGT.
These results indicate that when specific assays for insulin are used, Asian subjects show postglucose load hyperinsulinemia and fasting hyperproinsulinemia compared with white subjects, suggesting increased insulin secretion and/or the presence of underlying insulin resistance in this ethnic group. The contribution of proinsulin-like molecules to total insulin-like molecules was similar between Asian and white subjects with NGT and IGT, and there was no contribution to hyperinsulinemia in Asian subjects.
研究完整胰岛素原和去31,32 -胰岛素原对两个种族（亚洲人和白人）非糖尿病受试者空腹胰岛素样分子浓度的贡献，并使用高特异性胰岛素检测方法，观察亚洲受试者与白人受试者相比是否存在高胰岛素血症。
我们调查了根据世界卫生组织标准诊断为糖耐量正常（NGT）（82名亚洲人和67名白人）和糖耐量受损（IGT）（16名亚洲人和13名白人）的受试者。使用基于高特异性单克隆抗体的检测方法来测量胰岛素、完整胰岛素原和去31,32 -胰岛素原。胰岛素分泌指数通过口服葡萄糖耐量试验中0至30分钟内胰岛素增量与葡萄糖增量浓度之比得出。
NGT的亚洲受试者尽管比白人明显瘦（BMI 24.4±3.5 vs. 25.7±3.7 kg/m²，P = 0.04），但肥胖的中心分布更明显（肩胛下与三头肌皮褶厚度比1.36±0.69 vs. 1.17±0.41，P = 0.047）。NGT的亚洲受试者口服葡萄糖负荷后2小时显示出明显的高胰岛素血症（血浆胰岛素中位数274 pmol/l [范围26 - 1,505] vs. 186 pmol/l [27 - 720]，P < 0.005），与白人相比。NGT的亚洲受试者与白人受试者相比，胰岛素增量也显著更高（P < 0.02），完整胰岛素原的空腹浓度也显著更高（中位数2.7 pmol/l [范围0.9 - 14.1] vs. 2.1 [0.8 - 7.9]，P < 0.02），但去31,32 -胰岛素原并非如此。然而，NGT和IGT的亚洲受试者与白人受试者之间，胰岛素原样分子与三种胰岛素样分子总和的比值相似。
这些结果表明，当使用胰岛素特异性检测方法时，与白人受试者相比，亚洲受试者在葡萄糖负荷后显示高胰岛素血症和空腹高胰岛素原血症，提示该种族胰岛素分泌增加和/或存在潜在的胰岛素抵抗。NGT和IGT的亚洲受试者与白人受试者之间，胰岛素原样分子对总胰岛素样分子的贡献相似，且对亚洲受试者的高胰岛素血症无影响。
