[Effects of glucagon on plasma ghrelin level in type 2 diabetes mellitus].

Objective: To investigate the effect of glucagon on ghrelin secretion in type 2 diabetes mellitus (T2DM) patients.

Methods: Circulating ghrelin and C-peptide were measured during glucagon stimulation test in 38 cases with T2DM and 30 cases in normal controls (NC) at the 1st Affiliated Hospital of Shantou University from May 2006 to December 2007.

Results: (1) There was no significant difference in the fasting C-peptide and fasting ghrelin levels of the NC group were (1.3 +/- 0.6) microg/L and (3.0 +/- 1.0) ng/ml respectively, both not significantly different from those of the T2DM group [(1.2 +/- 0.4) microg/L and (2.7 +/- 0.8) microg/L respectively, P > 0.05 and P > 0.05]; six minutes after the injection of glucagon, the C-peptide level of the T2DM group increased to (2.0 +/- 0.8) microg/L (P < 0.01), and that of the NC group increased to (3.0 +/- 0.8) microg/L (P < 0.01), and the C-peptide level 6 min after of the T2DM group was significantly lower than that of the NC group (P < 0.01). The ghrelin level 6 min after the injection of glucagon of the NC group was (2.3 +/- 0.7) microg/L, significantly lower than that before the injection (P < 0.01). But the ghrelin level 6 min after the injection of glucagon of the T2DM group was (2.9 +/- 0.9) microg/L, NOT significantly different from that before the injection (P > 0.05). (2) Fasting ghrelin level was significantly negatively correlated with the waist circumference (r = -0.343, P < 0.05).

Conclusion: In healthy subjects exogenous glucagon decreases the ghrelin level. Ghrelin may be associated with the beta-cell hypofunction and first-phase insulin secretion defects in T2DM. Insulin, glucagon, and ghrelin secreted influence each other to regulate glucose homeostasis.