Activation of Mitogen-activated protein kinase (MAPK) by GnRH is cell-context dependent

The interaction of GnRH with its cognate receptor (GnRHR) in pituitary gonadotropes includes activation of Gq/G(11) and phospholipase CP (PLC beta), which generates the second messengers inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG), which are required for Ca2+ mobilization and PKC isoforms activation. Activation of PKC in pituitary gonadotropes leads to the activation of the major members of the mitogen-activated protein kinase superfamily (MAPK), namely: extracellular signal-regulated kinase (ERK), jun-N-terminal Kinase (INK) and p38MAPK. The above pathways mediate GnRH-induced gonadotropin release and synthesis.,Here we summarise the diverse mechanisms utilized by GnRH to activate the MAPK members and show that they depend on "cell-context". (c) 2006 Published by Elsevier Ireland Ltd.