Phospholipid Turnover, Ca2+ Mobilization and Protein Kinase C Activation in GnRH Action on Pituitary Gonadotrophs
Gonadotropin releasing hormone (GnRH) binds to pituitary gonadotrophs (LH + FSH containing cells) and stimulates the biosynthesis and release of the gonadotropins. Peptide hormones in general exert their biological effects via the formation of’ second messengers’. The messenger molecule activates a respective protein kinase resulting in the phosphorylation and activation of key proteins and enzymes, and hence in the physiological response (Greengard, 1978). The classical’ second messengers’ cAMP, cGMP and prostaglandins were ruled out as potential mediators of the acute actions of GnRH (for review see Naor, 1982). On the other hand, Ca2+ mobilization and phospholipid turnover were implicated in the hormone action (Pickering and Fink, 1979? Naor and Catt, 1981; Naor et al., 1980; 1985a; Conn et al., 1981; Snyder and Bleasdale, 1982; Raymond et al., 1984; Kiesel and Catt, 1984; Schrey, 1985). In this chapter we will review the recent findings, from several laboratories, concerning the mechanism of action of GnRH.
KeywordsLuteinizing Hormone Phosphatidic Acid Pituitary Cell Phosphatidic Acid Anterior Pituitary Cell
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