Hyperglucagonemia and impaired insulin sensitivity are associated with development of prediabetes and type 2 diabetes - A study from South India.

Background And Aims: Glucagon levels and glucagon suppression in response to oral glucose load has not been elucidated at different stages of glucose intolerance in India.

Methods: A total of 81 subjects underwent OGTT and were classified into three groups as having normal glucose tolerance (NGT) (n = 23), prediabetes (PreDM) (n = 33), newly diagnosed diabetes (NDM) (n = 25). Insulin and glucagon at fasting, 30 and 120 min was measured by ELISA. HOMA-IR, measures of insulin sensitivity, early, late and overall glucagon suppression during OGTT was calculated.

Results: Plasma glucagon levels were higher at all-time points in the PreDM and NDM groups. Fasting glucagon levels were higher than post glucose load glucagon in all groups. There was a significant difference in the fasting(p = 0.001), 30 min(p = 0.004) and 120 min(p = 0.032) glucagon between the groups. HOMA-IR increased and insulin sensitivity decreased with worsening of glucose intolerance(p < 0.0001). The groups did not differ in terms of early glucagon suppression(p = 0.094). NDM group suppressed glucagon more than NGT from 30 to 120 min after glucose intake.

Conclusion: This study demonstrated higher fasting glucagon levels. Prediabetes and newly diagnosed diabetes individuals had higher glucagon levels, high insulin resistance and lower insulin sensitivity. Hyperglucagonemia may contribute to type 2 diabetes.