Fasting and postprandial plasma glucagon and glucagon-like immunoreactivity are normal in obese Pima Indians

Glucose, insulin (IRI), glucagon (IRG) and GLI were measured in plasma samples obtained from 32 subjects representing a wide range of body weight (body mass index = 21 - 49 kg/m²) after an overnight fast and for 6 hr following ingestion of a standard test meal. The 6 hr integrated postprandial response of each hormone was estimated for each subject from the area of the response curve above basal concentration. Both fasting (r = 0.72, p < 0.0001) and postprandial (r = 0.45, p < 0.01) IRI were significantly correlated with degree of obesity, as expected. However, the fasting and postprandial plasma glucagon and glucagon-like immunoreactivity levels were not related to obesity of the subject and were not different for the obese (BMI > 35, n = 16) and nonobese (BMI < 30, n = 12) groups. Thus, there is no evidence for an abnormality in the response of these peptide hormones to a mixed meal in this obese population.