Effects of glucagon on islet beta cell function in patients with diabetes mellitus.
OBJECTIVE
To evaluate islet beta cell response to intravenous glucagon (a non-glucose secretagogue) stimulation in diabetes mellitus.


METHODS
Nineteen patients with type 1 diabetes (T1D) and 131 patients with type 2 diabetes (T2D) were recruited in this study. T2D patients were divided into two groups according to therapy: 36 cases treated with insulin and 95 cases treated with diet or oral therapy. The serum C-peptide levels were determined at fasting and six minutes after intravenous injection of 1 mg of glucagon.


RESULTS
Both fasting and 6-minute post-glucagon-stimulated C-peptide levels in T1D patients were significantly lower than those of T2D patients (0.76 +/- 0.36 ng/mL vs. 1.81 +/- 0.78 ng/mL, P < 0.05; 0.88 +/- 0.42 ng/mL vs. 3.68 +/- 0.98 ng/mL, P < 0.05). In T1D patients, the C-peptide level after injection of glucagon was similar to the fasting level. In T2D, patients treated with diet or oral drug had a significantly greater fasting and stimulated C-peptide level than those patients received insulin therapy (2.45 +/- 0.93 ng/mL vs. 1.61 +/- 0.68 ng/mL, P < 0.05; 5.26 +/- 1.24 ng/mL vs. 2.15 +/- 0.76 ng/mL, P < 0.05). The serum C-peptide level after glucagon stimulation was positively correlated with C-peptide levels at fasting in all three groups (r = 0.76, P < 0.05).


CONCLUSIONS
The 6-minute glucagon test is valuable in assessing the function of islet beta cell in patients with diabetes mellitus. It is helpful for diagnosis and treatment of diabetes mellitus.
Wang
Tong
T
Key Laboratory of Endocrinology of Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730.
Xiao
Xin-Hua
XH
Li
Wen-Hui
WH
Wang
Heng
H
Sun
Qi
Q
Yuan
Tao
T
Yang
Guo-Hua
GH
D000328:Adult; D002096:C-Peptide / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D005260:Female; D005934:Glucagon / Q000494:pharmacology / Q000627:therapeutic use; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000627:therapeutic use; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008875:Middle Aged
D002096:C-Peptide; D005934:Glucagon; D006442:Glycated Hemoglobin; D007328:Insulin; C517652:hemoglobin A1c protein, human