精氨酸刺激后2分钟胰岛素原所占比例的初步研究

目的探讨和寻找简易的、临床上可行的评估胰岛β细胞功能的方法。方法2001年11月至2002年8月本院住院及门诊患者和本院职工214例,均为居住在上海地区的汉族人,按1999年世界卫生组织(WHO)标准诊断,分为4组,其中正常糖耐量(NGT)组39例、糖耐量受损(IGT)组29例、新诊断2型糖尿病(NT2DM)组43例和原诊断2型糖尿病(PT2DM)组103例。分别检测其空腹及精氨酸刺激后2、4、6min时血糖、真胰岛素(TI)及胰岛素原(PI)水平的变化。结果(1)空腹PI/TI、PI/(TI+PI)在NGT组(19·09%±2·02%和15·31%±1·14%)显著低于IGT组(38·83%±6·80%和24·43%±2·43%,均P<0·05)。(2)精氨酸刺激后TI/血糖分泌曲线由高到低依次为IGT、NGT、NT2DM、PT2DM。PI与PI/血糖在IGT、NT2DM、PT2DM组均于2min时达峰值。(3)PI/TI各组改变与上述TI/血糖改变成镜像现象,并在2min时达低谷值(NGT2·99%±0·27%,IGT6·70%±1·38%,NT2DM10·52%±1·46%,PT2DM11·12%±1·51%)。PI/(TI+PI)变化趋势及差异的显著性与PI/TI相似,此两个参数的2min低谷值由小到大排列顺序为NGT、IGT、NT2DM、PT2DM。结论精氨酸刺激后2min的PI/TI及PI/(TI+PI)值可作为临床评估β细胞功能的一个简易而实用的指标。

Proportion of proinsulin two minutes after arginine stimulation: a pilot study

OBJECTIVE: To seek an easy way to evaluate islet beta cell function. METHODS: 214 residents of Shanghai, aged 20-70, all of Han nationality, were divided into 3 groups according the 1999 WHO standard: 39 in the normal glucose tolerance (NGT) group, aged 52 years +/- 6 years, with the BMI of 22.3 kg/m(2) +/- 0.4 kg/m(2); 29 in the impaired glucose tolerance (IGT) group, aged 54 years +/- 9 years, with the BMI of 24.4 kg/m(2) +/- 0.6 kg/m(2); and 146 in the T2DM group, that was subdivided into 2 subgroups: 43 in the newly diagnosed T2DM (NT2DM) group, aged 52 years +/- 9 years, with the BMI of 24.4 kg/m(2) +/- 0.5 kg/m(2), and 103 in the previously diagnosed T2DM (PT2DM) group, aged 57 years +/- 9 years, with the BMI of 23.5 kg/m(2) +/- 0.3 kg/m(2). Arginine at the dose of 10% 50 ml was injected intravenously in fasting situation. Two, four, and six minutes after blood samples were collected from a needle indwelling in the contralateral vein to examine the levels of plasma glucose (PG), true insulin (TI), and proinsulin (PI). RESULTS: (1) The TI and TI/PG levels of all groups peaked 2 minutes after arginine stimulation and then gradually decreased, however, the levels 6 minutes after stimulation were still higher than the baseline values. The peak values of TI and TI/PG were arranged from high to low in the order of IGT, NGT, NT2DM and PT2DM. The peak values of NT2DM and PT2DM groups were significantly lower than those of the NGT and IGT groups (all P < 0.01). The peak values of the NT2DM group were significantly higher than those of the PT2DM group (both P < 0.01). (2) The PI value of the IGT, NT2DM and PT2DM groups peaked 2 minutes after the stimulation and then gradually decreased with the peak values significantly higher than that of the NGT group (all P < 0.05). The fasting PI/TI and PI/(TI + PI) of the NGT group were all significantly lower than those of the IGT group (both P < 0.05). (3) The changes of PI/TI in each groups manifested almost the mirror image of TI/PG mentioned above, and the lowest PI/TI levels were observed 2 minutes after stimulation. The similar changes of PI/(TI + PI) were found. The lowest points of groups 2 minutes after stimulation was arranged from low to high in the order of NGT, IGT, NT2DM and PT2DM. CONCLUSION: The PI/TI and PI/(TI + PI) values 2 minutes after arginine stimulation may be used as predictors for beta cell function in clinical practice.