Sun Xiao-Hui, Wang Yan-Gang, Qi Yu-Qin, Wang Luan, Chen Ying
Department of Endocrinology, The Affiliated Hospital of Medical College Qingdao University, Qingdao 266003, China.
Zhonghua Nei Ke Za Zhi. 2010 Jan;49(1):19-23.
To explore the impact of genetic background on pancreatic beta-cell first-phase secretion function with L-arginine (L-ARG) stimulation test.
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).
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.
In the early course of diabetes, insulin resistance dose not function significantly, but genetic background make the first-phase secretory function of the beta-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.
通过L-精氨酸（L-ARG）刺激试验探讨遗传背景对胰岛β细胞第一时相分泌功能的影响。
对201例受试者进行L-ARG刺激试验，分别检测试验前后血浆胰岛素水平。其中新诊断2型糖尿病伴糖尿病家族史（FH+DM）61例，新诊断2型糖尿病不伴糖尿病家族史（FH-DM）55例，糖耐量正常伴糖尿病家族史（FH+）31例，糖耐量正常不伴糖尿病家族史（FH-）54例。采用稳态模型评估（HOMA）法估算胰岛素抵抗（HOMA-IR）。
4组间性别、年龄及体重指数（BMI）相近。（1）新诊断的2型糖尿病伴或不伴糖尿病家族史的两组患者的总胆固醇（TC）、甘油三酯（TG）、空腹血糖、餐后2小时血糖、空腹胰岛素及HOMA-IR均显著高于糖耐量正常伴或不伴糖尿病家族史的两组。新诊断糖尿病组胰岛素分泌峰值水平与基础水平的倍数显著低于糖耐量正常伴家族史组和糖耐量正常不伴家族史组（P<0.05）。（2）4组胰岛素分泌均在2分钟时达峰值，4分钟时开始下降。（3）糖耐量正常伴糖尿病家族史组胰岛素分泌峰值水平与基础水平的倍数比糖耐量正常不伴家族史组低20.8%，分别为7.27和9.18（P<0.05）。（4）新诊断2型糖尿病伴糖尿病家族史组的2分钟胰岛素分泌峰值、HOMA-IR及年龄显著低于新诊断2型糖尿病不伴糖尿病家族史组（P<0.05）。新诊断2型糖尿病伴糖尿病家族史组与新诊断2型糖尿病不伴糖尿病家族史组胰岛素分泌峰值水平与基础水平的倍数分别为5.18和5.31，两组间差异无统计学意义（P>0.05）。（5）糖耐量正常伴糖尿病家族史者进展为糖尿病时，胰岛素分泌峰值水平与基础水平的倍数较糖耐量正常不伴家族史者下降43.6%（P<0.05）。
在糖尿病早期，胰岛素抵抗作用不明显，但遗传背景使β细胞第一时相分泌功能逐渐下降，易发生2型糖尿病。在无遗传背景时，胰岛素抵抗使胰岛素第一时相分泌下降相对缓慢。
