541-P: Glucagon Prevents Rat Dorsal Root Ganglion Neurons from Cell Stress Induced by Methylglyoxal

Background: Glucagon is a peptide hormone produced by the alpha cells of the pancreas. Other than gluconeogenesis, glucagon has many pleiotropic effects on feeding, energy expenditure, and thermogenesis. Our recent studies revealed that glucagon promoted neurite outgrowth in a primary culture of mouse dorsal root ganglion (DRG) neurons. Therefore, glucagon might have a neuroprotective function in the peripheral nervous system. To clarify the protective function, we use an immortalized rat embryonic DRG neuronal cell line 50B11 as an in vitro model to study the effects of glucagon in DRG neurons. Methods: Expression of glucagon receptor in the DRG neurons was examined by RT-PCR. The cells were cultured with or without glucagon (10-8, 10-10 M) for 24 hours. To reproduce the cell stress, cells were cultured with methylglyoxal (MG). Cell cytotoxicity was examined by lactate dehydrogenase assay. Cell viability was evaluated using the MTS assay. The apoptosis was also examined by APOPercentageTM dye. Result: Glucagon receptor was expressed in the 50B11 cell line. The glucagon itself had no effect on cytotoxicity in the cells. The cell viability decreased by MG was significantly increased in the group treated with glucagon. The ratio of apoptotic cells, which was increased by MG, was decreased in the group treated with glucagon. Conclusion: Glucagon may have a protective role in DRG neurons. Further investigation is necessary to determine the detailed action of glucagon in DRG neurons.