MECHANISMS OF HORMONE ACTION - LUTEINIZING-HORMONE RECEPTORS AND 2ND-MESSENGER PATHWAYS

The binding of luteinizing hormone/chorionic gonadotropin (LH/CG) to i ts receptor leads to an orderly cascade of events leading to activatio n of cytoplasmic effector molecules. The mechanism of action of LH inc ludes stimulation of multiple signal transduction effector systems, in cluding adenylyl cyclase (AC) and inositol phospholipid-specific phosp holipase-C (PLC). These effector systems operate by activating familie s of protein kinases (PKs) which regulate cell metabolism, secretion, gene induction, cellular proliferation and differentiation. The signal ing pathways activated by LH interact or cross-talk with the signaling pathways activated by growth factors. The diversity of cellular signa ling mechanisms elicited by LH and the potential for interactions with signals generated by growth factors may allow fine tuning of cellular responses during the process of follicular development, ovulation, an d corpus luteum formation.