空腹血糖水平与精氨酸刺激后胰岛素急性分泌的关系

目的 探讨不同糖代谢状况下空腹血糖水平与精氨酸刺激后胰岛素急性分泌的关系.方法 入选2004至2005年来我院门诊就诊者及健康志愿者626例,其中糖耐量正常114例,糖耐量受损60例,新诊断2型糖尿病452例.在我院内分泌科门诊接受葡萄糖耐量试验及精氨酸试验.测定空腹血糖、胰岛素原及真胰岛素水平,评估精氨酸刺激后胰岛素急性分泌相(△TI).采用稳态模型计算胰岛素抵抗指数(HOMA-IR).运用协方差分析或非参数检验进行统计学分析.结果 空腹血糖为3.8～5.0 mmol/L时,△TI由34.13 mmol/L逐渐升至41.50 mmol/L;空腹血糖为5.0 mmol/L时,△TI达到峰值41.50 mmol/L,之后轻度下降;空腹血糖为6.1～10.0 mmol/L时,△TI持续下降并形成平台,较峰值降低近35%;空腹血糖>10.0 mmol/L时,△TI显著减退;空腹血糖>11.1 mmol/L时,△TI达17.40 mmol/L,较峰值降低近60%.空腹血糖为3.8～6.1 mmol/L时,胰岛素原分泌迅速由0.01 pmol/L增至6.96 pmol/L;空腹血糖为6.1～10.0 mmol/L时,胰岛素原分泌持续缓慢增加,并达到峰值10.84 pmol/L;空腹血糖>10.0 mmol/L时,胰岛素原分泌呈显著下降趋势.空腹血糖由3.8 mmoL/L增至7.8 mmol/L时,HOMA-IR呈上升趋势;空腹血糖>7.8 mmol/L时,HOMA-IR维持较高水平(6.82)并处于平台.结论 空腹血糖为6.1～10.0 mmol/L时,精氨酸刺激后胰岛素急性分泌相相对稳定,表明胰岛β细胞尚具有较好的储备功能.空腹血糖>10.0 mmol/L时,精氨酸试验激发后△TI及胰岛素原显著下降,提示胰岛β细胞功能严重衰竭.

Fasting glucose level and acute insulin secretion stimulated by arginine

Objective To explore the relationship between fasting plasma glucose (FPG) and acute insulin secretion stimulated by arginine. Methods A total of 626 adults [normal glucose tolerance (n=114), impaired glucose tolerance (n=60), and newly diagnosed type 2 diabetes mellitus (n=452)]were enrolled in this study from 2004 to 2005. All the participants received oral glucose tolerance test and arginine stimulation test. FPG, proinsulin (PI), and true insulin (TI) were measured. Acute insulin release function (△TI) and HOMA-IR were assessed. Covariance analysis and non-parameter test were used for data analysis. Results △TI increased from 34. 13 to 41.50 mmol/L when FPG was 3. 8 to 5.0 mmol/L and reached the peak of 41.50 mmol/L when FPG was 5.0 mmol/L, then decreased gradually with FPG increasing. When FPG was 6. 1 to 10. 0 mmol/L, △TI reached the platform and decreased by about 35% compared with the peak △TI. When FPG was > 10. 0 mmol/L, △TI descended abruptly. △TI declined by about 60% when FPG was > 11.1 mmol/L PI gradually increased from 0. 01 to 6.96 pmol/L when FPG was 3.8 to 10.0 mmol/L. However, PI decreased when FPG was > 10. 0 mmol/L. Insulin resistance index (HOMA-IR) was elevated with the increase of FPG. When FPG was >7. 8 mmol/L, HOMA-IR remained high (6.82) and reached the platform. Conclusions Acute insulin release stimulated by arginine was relatively stable when FPG was 6. 1 to 10. 0 mmol/L, suggesting detectable reserved β cell function. Both △TI and PI were significantly decreased in the arginine stimulation test when FPG was > 10.0 mmol/L,indicating that the acute insulin release function might be severely damaged.