Glutamate Signals Insulin Secretion

Science's STKE  14 Dec 1999:
Vol. 1999, Issue 12, pp. tw5
DOI: 10.1126/stke.1999.12.tw5

Release of insulin from pancreatic ╬▓cells in response to glucose is thought to be signaled by generation of ATP and consequent influx of calcium into the cell. However, evidence indicates that a factor besides ATP is released from mitochondria that is necessary for secretion. Maechler and Wollheim provide evidence that this messenger is glutamate. Glutamate is shown to be generated by mitochondria in response to glucose and directly stimulates exocytosis in permeabilized cells in which the concentration of calcium is held constant. Uptake of glutamate by secretory granules appears to be required for its effects. Thus, glutamate, well known as an intercellular messenger in the nervous system, appears to also function as an intracellular messenger that controls insulin secretion.

Maechler, P., and Wollheim, C.B. (1999) Mitochondial glutamate acts as a messenger in glucose-induced insulin exocytosis. Nature 402: 685-689. [Online Journal]