Increment of plasma glucose by exogenous glucagon is associated with present and future renal function in type 2 diabetes:a retrospective study from glucagon stimulation test

Background Glucagon stimulation test (GST) is often employed to assess the insulin reserve of the pancreatic beta cells in diabetic subjects. The clinical significance of the increment of plasma glucose (Delta glucose) by exogenous glucagon during GST has not been elucidated. We investigated the relationship between Delta glucose and clinical parameters including the liver and renal function in type 2 diabetic subjects, since we hypothesized that Delta glucose is associated with the liver and renal function reflecting the capacity for gluconeogenesis in the organs. Methods A total of 209 subjects with type 2 diabetes who underwent GST during admission were included in this cross-sectional study. We defined the difference between plasma glucose at fasting and 6 min after intravenous injection of 1 mg glucagon as Delta glucose. We assessed correlations between Delta glucose and clinical parameters such as diabetic duration, BMI, HbA1c, beta cell function, serum free fatty acids (FFA) which is known to stimulate gluconeogenesis, liver function, the indices of liver function, renal function, and urinary albumin excretion (UAE). Results In correlation analysis, Delta glucose positively correlated to FFA and estimated glomerular filtration rate (eGFR), but inversely to serum creatinine and cystatin C, although Delta glucose showed no correlation with both liver function and the indices of residual liver function. Multiple regression analysis revealed that Delta glucose was an independent determinant for the eGFR after 1 year, equally BMI, HbA1c, serum lipids, and UAE, which are known as the predictors for the development of chronic kidney disease. Conclusion Our results suggest that Delta glucose during GST might be related to gluconeogenesis in the kidney and could be the determinant of future renal function in type 2 diabetes.