左旋精氨酸刺激试验评价遗传背景对正常糖耐量者和初诊糖尿病患者胰岛β细胞功能的影响

目的 探讨遗传背景对左旋精氨酸(L-ARG)刺激后胰岛β细胞第一时相分泌功能的影响.方法 检测201例L-ARG刺激前后胰岛素值,其中有家族史初诊2型糖尿病患者(FH+DM)61例、无家族史初诊2型糖尿病患者(FH-DM)55例、有家族史正常糖耐量者(FH+)31例、无家族史正常糖耐量者(FH-)54例.以HOMA胰岛素抵抗指数(HOMA-IR)评价胰岛素抵抗.结果 校正性别、年龄、BMI后,(1)糖尿病组(FH+DM和FH-DM)TC、TG、空腹血浆血糖(FPG)、糖负荷后2 h血糖、空腹胰岛素(Fins)、HOMA-IR明显高于糖耐量正常组(FH+和FH-),胰岛素峰值倍数明显低于糖耐量正常组,P<0.05;(2)4组胰岛素均2 min达分泌峰值,4 min开始下降;(3)FH+组胰岛素峰值倍数较FH-组下降20.8%,分别为7.27与9.18倍,P<0.05;(4)FH+DM组2 min胰岛素分泌峰值、HOMA-IR、患病年龄明显低于FH-DM组(P<0.05),两组峰值倍数分别为5.18与5.31倍,差异无统计学意义(P>0.05);(5)FH+DM组胰岛素峰值倍数较FH-组下降了 43.6%(P<0.05).结论 2型糖尿病早期,尽管胰岛素抵抗表现不显著,遗传背景却使胰岛β细胞第一时相分泌功能减退;而无遗传背景者,胰岛素抵抗使胰岛素第一时相分泌下降相对缓慢.

Evaluation of the impact of genetic background on islet p-cell function of normal glucose tolerance and newly diagnosed diabetic patients by L-arginine stimulation test

Objective To explore the impact of genetic background on pancreatic p-cell first-phase secretion function with L-arginine (L-ARG) stimulation test.Methods Plasma insulin level was detected in 201 cases before and after L-ARG stimulation test.Among them, 61 cases were newly diagnosed type 2 diabetic patients with family history of diabetes ( FH + DM ) , 55 newly diagnosed type 2 diabetic patients without family history of diabetes ( FH - DM) ,31 with normal glucose tolerance and family history of diabetes ( FH + ) 54 with normal glucose tolerance but without family history of diabetes ( FH - ).Homeostasis model assessment ( HOMA) was used to estimate insulin resistance (HOMA-IR).Results It was premised that gender, age and BMI were similar among the 4 groups.(1)TC,TG,fasting plasma glucose,2h plasma glucose,fasting insulin and HOMA-IR in the two groups of newly diagnosed type 2 diabetic patients with or without family history of diabetes were significantly higher than those in the two groups of normal glucose tolerance with or without family history of diabetes.The multiples of the peak level and the base level of insulin secretion in the groups of newly diagnosed diabetes were significantly lower than those in the groups of normal glucose tolerance with and without family history(P <0.05).(2) Insulin secretion reached a peak in 2 minutes and started to decline in 4 minutes in all the four groups.( 3 ) The multiples of the peak level and the base level of insulin secretion in normal glucose tolerance group with family history of diabetes were 20.8% lower than those in the group without family history, being 7.27 and 9.18 respectively ( P < 0.05 ).(4)Two-minute peak insulin secretion, HOMA-IR and age in the newly diagnosed type 2 diabetic group with family history of diabetes was significantly lower than these in the group without family history ( P < 0.05 ).The multiples of the peak level and the base level of insulin secretion in the newly diagnosed type 2 diabetic group with family history of diabetes and that group without family history were 5.18 and 5.31 respectively and there was no significant difference between the two groups( P >0.05).(5) When the normal glucose tolerance subjects with family history of diabetes progressed to suffer from diabetes, the multiples of the peak level and the base level of insulin secretion declined 43.6% (P < 0.05) more than those in the subjects still with normal glucose tolerance without family history.Conclusion In the early course of diabetes, insulin resistance dose not function significantly, but genetic background make the first-phase secretory function of the p-cell to decline gradually and type 2 diabetes occurs easily.In the absence of genetic background, insulin resistance makes first-phase the secretion of insulin to decline relatively slow.