Also, insulin and glucagon have a role in energy balance regulation [10,11]. The current study is, therefore, designed to analyze serum glucagon levels in subjects with T2DM and impaired glucose tolerance compared to normal glucose tolerance and to evaluate the correlation of fasting glucagon with fasting and 2-hour plasma glucose (2-hPG), glycated hemoglobin (HbA1c), lipid profile, and anthropometric parameters specifically with the parameters of central obesity in the study population. The gene discussed is GCG; the disease is type 2 diabetes mellitus.