The purpose of this review is to update the information concerning the intracellular effect of GnRH. Binding of GnRH to a G-protein coupled receptor leads to stimulation of Gq and/or G11 protein and to activation of phospholipase C beta. Inositol 1-4-5-triphosphate and early diacylylycerol are the second messengers required for conventional protein kinase C activation. Activation of phospholipase A2 and phospholipase D are also involved, as demonstrated by the liberation of Arachidonic Acid and Phosphatidic Acid. Pituitary cells also express atypical protein kinase C isoforms which mode of activation is not known. Hypothesis concerning transcriptional regulation are presented.