[Characteristics of dysfunction of islet beta-cell in newly diagnosed type 2 diabetic patients].
OBJECTIVE
To investigate the characteristics of the dysfunction of islet beta-cell in newly diagnosed type 2 diabetic patients.


METHODS
Intravenous glucose tolerance test (IVGTT) was carried out on 352 newly diagnosed type 2 diabetic patients and 48 subjects with normal glucose tolerance (NGT) and then blood samples were collected 1, 2, 4, 6, and 10 minutes later to measure the plasma glucose and insulin to calculate the acute insulin response (AIR) and the area under the curve of insulin (AUC of insulin), homeostasis model assessment beta-cell (Homabeta), and Homa IR (insulin resistance).


RESULTS
The median AIR of the type 2 diabetic patients was -33.7 pmol/L, significantly lower than that of the NGT subjects (6962.0 pmol/L, P < 0.001). The median AUC of the type 2 diabetic patients was 834.2 pmol/L, significantly lower than that of the NGT subjects (7934.7 pmol/L, P < 0.001). When the fasting plasma glucose (FPG) of the type 2 diabetic patients was above 7.0 mmol/L, the AIR value was remarkably reduced with a median level of 317.3 pmol/L, and then subsequently disappeared when the FPG was above 9.0 mmol/L. After adjustment of the insulin resistance assessed by HOMA IR, the Homabeta of the type 2 diabetic patients was reduced to be 30% that of the NGT subjects (3.7 +/- 0.9 vs 5.9 +/- 0.9, P < 0.001). Both the fasting proinsulin concentration and the ratio of fasting proinsulin to fasting insulin of the type 2 diabetic patients were significantly higher those of the NGT subjects (22.6 pmol/L +/- 14.7 pmol/L vs 11.5 pmol/L +/- 7.1 pmol/L, P < 0.001; and 30.1% +/- 20.5% vs. 12.1% +/- 9.6%, P < 0.001).


CONCLUSIONS
The dysfunction of islet beta-cell in newly diagnosed type 2 diabetic patients is mainly represented by the disappearance of AIR and the evident decline of AUC and HOMA B, and the decrease of quality of insulin secretion.
Li
Yan-bing
YB
Department of Endocrinology, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China.
Zhu
Da-long
DL
Tian
Hao-ming
HM
Shi
Li-xin
LX
Luo
Zuo-jie
ZJ
Yan
Li
L
Zeng
Long-yi
LY
Zhou
Zhi-guang
ZG
Yang
Li-yong
LY
Liu
Juan
J
Li
Ming
M
Weng
Jian-ping
JP
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood* / Q000378:metabolism; D007333:Insulin Resistance; D007515:Islets of Langerhans / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011384:Proinsulin / Q000097:blood / Q000378:metabolism
D001786:Blood Glucose; D007328:Insulin; D011384:Proinsulin