Estrogen signaling in hypothalamic circuits controling reproduction

It is well known that many of the actions of 17 beta estradiol (E2) in the central nervous system are mediated via intracellular receptor/transcription factors that interact with steroid response elements on target genes However, there is compelling evidence for membrane steroid receptors for estrogen in hypothalamic and other brain neurons Yet, it is not well understood how estrogen signals via membrane receptors and how these signals impact not only membrane excitability but also gene transcription in neurons that modulate GnRH neuronal excitability Indeed it has been known for some time that E2 can rapidly alter neuronal activity within seconds indicating that some cellular effects can occur via membrane delimited events In addition E2 can affect second messenger systems including calcium mobilization and a plethora of kinases to alter cell signaling Therefore this review will consider our current knowledge of rapid membrane initiated and intracellular signaling by E2 in hypothalamic neurons critical for reproductive function (C) 2010 Elsevier B V All rights reserved