Nongenomic membrane actions of glucocorticoids in vertebrates

For decades, it was widely assumed that glucocorticoids (GCs) work solely t hrough changes in gene expression to exert their physiological actions, a p rocess that normally takes several hours to occur. However; recent evidence indicates that GCs might also act at the membrane through specific recepto rs to exert multiple vapid effects on various tissues and cells. GCs modula te hormone secretion, neuronal excitability, behavior; cell morphology, car bohydrate metabolism and other processes within seconds or minutes. These e arly actions occur independent of the genome and are transduced by the same biochemical effector path ways responsible for mediating rapid responses t o neurotransmitters. The biological significance of most rapid GC effects a re not well understood but many might be related to the important functions that this hormone plays in modulating stress responses.