SIGNAL-TRANSDUCTION OF THE GONADOTROPIN-RELEASING-HORMONE (GNRH) RECEPTOR - CROSS-TALK OF CALCIUM, PROTEIN-KINASE-C (PKC), AND ARACHIDONIC-ACID

1. The decapeptide neurohormone gonadotropin releasing hormone (GnRH) is the first key hormone of the reproductive system, Produced in the h ypothalamus, GnRH is released in a pulsatile manner into the hypophysi al portal system to reach the anterior pituitary and stimulates the re lease and synthesis of the gonadotropin hormones LW and FSH, GnRH, a C a2+ mobilizing ligand, binds to its respective binding protein, which is a member of the seven transmembrane domain receptor family and acti vates a G-protein (Gq). 2. The alpha subunit of Gq triggers enhanced p hosphoinositide turnover and the elevation of multiple second messenge rs requried for gonadotropin release and biosynthesis. 3. The messenge r molecules IP3, diacylglycerol, Ca2+, protein kinase C-4 arachidonic acid and leukotriene C-4 cross-talk in a complex networks of signaling , culminating in gonadotropin release and gene expression.