The aims of the present study were to investigate the performance of a novel sandwich enzyme-linked immunosorbent assay (ELISA) for measuring glucagon (1–29) with monoclonal antibodies against both the C- and N-terminal regions of glucagon (1–29), and to analyze the differences in plasma levels and responses of glucagon (1–29) to oral glucose loading in normal glucose tolerance (NGT) subjects and patients with type 2 diabetes mellitus.Materials and Methods:
The cross-reactivity against proglucagon fragments using the ELISA kit and two types of conventional radioimmunoassay (RIA) kits was evaluated. A 75-g oral glucose tolerance test was carried out with NGT subjects and patients with type 2 diabetes mellitus, and the glucagon (1–29) concentration was measured using three types of kit.Results:
The ELISA kit clearly had the lowest cross-reactivity against miniglucagon (19–29) and glicentin (1–61). The oral glucose tolerance test was carried out with 30 NGT and 17 patients with type 2 diabetes mellitus. The glucagon (1–29) levels measured by the ELISA kit after glucose loading were significantly higher at all time-points in the type 2 diabetes mellitus group than in the NGT group. However, the glucagon (1–29) levels measured by one RIA kit were significantly higher in the NGT group, and those measured with the other RIA kit were approximately the same among the groups.Conclusions:
The novel sandwich ELISA accurately determines plasma glucagon (1–29) concentrations with much less cross-reactivity against other proglucagon fragments than conventional RIA kits.
This study is declared that the novel sandwich ELISA can measure accurate plasma glucagon (1–29) concentrations with much less cross-reactivity against other pro-glucagon fragments than conventional RIA kits. Additionally, to use this kit for glucagon (1–29) measurement is able to estimate accurately the difference of the glucagon secretion between NGT and type 2 diabetes mellitus.