Section of Endocrinology, Department of Clinical Pathophysiology, University of Florence, Florence, Italy.
Diabet Med. 2010 Jun;27(6):691-5. doi: 10.1111/j.1464-5491.2010.03010.x.
The reduced levels of glucagon-like peptide 1 (GLP-1) after an oral glucose load in Type 2 diabetic patients could be dependent either on a reduced synthesis or an increased degradation; but GLP-1 and dipeptidyl peptidase IV (DPP-IV) levels during an oral glucose tolerance test (OGTT) have not been studied together. The aim of the present study was to investigate GLP-1 and DPP-IV levels during an OGTT in patients with different degrees of glucose tolerance.
Fifty six subjects (34 female, 22 male) matched for sex, age, body mass index (BMI) and waist circumference underwent a 75 g oral glucose tolerance test. Twenty-eight had normal glucose tolerance, 15 had impaired glucose tolerance and 13 had Type 2 diabetes mellitus. GLP-1 assay was performed with an ELISA kit, and DPP-IV assay using a colorimetric method.
At 30 min GLP-1 levels were significantly lower in subjects with impaired glucose tolerance and type 2 diabetes mellitus compared to those with normal glucose tolerance. The area under the GLP-1 curve was significantly different among the three groups; there was a significant decrease between subjects with normal and impaired glucose tolerance(P = 0.004) and between those with normal glucose tolerance and type 2 diabetes mellitus. (P < 0.001), while the area under the curve for DPP-IV showed no significant difference between the groups.
These results suggest that an increase of GLP-1 degradation does not play a role in the early stages of diabetes mellitus.
2 型糖尿病患者口服葡萄糖负荷后胰高血糖素样肽 1（GLP-1）水平降低，可能依赖于合成减少或降解增加；但尚未研究口服葡萄糖耐量试验（OGTT）期间 GLP-1 和二肽基肽酶 IV（DPP-IV）水平。本研究旨在研究不同糖耐量患者 OGTT 期间 GLP-1 和 DPP-IV 水平。
56 名受试者（34 名女性，22 名男性）按性别、年龄、体重指数（BMI）和腰围匹配，进行 75g 口服葡萄糖耐量试验。28 名受试者糖耐量正常，15 名受试者糖耐量受损，13 名受试者 2 型糖尿病。使用 ELISA 试剂盒检测 GLP-1，使用比色法检测 DPP-IV。
30 分钟时，糖耐量受损和 2 型糖尿病患者的 GLP-1 水平明显低于糖耐量正常者。三组间 GLP-1 曲线下面积差异显著；糖耐量正常者与糖耐量受损者之间（P=0.004）以及糖耐量正常者与 2 型糖尿病患者之间（P<0.001）差异有统计学意义，而 DPP-IV 曲线下面积无显著差异。
这些结果表明，GLP-1 降解增加在糖尿病早期阶段不起作用。
