Delayed activation of phospholipase D by gonadotropin-releasing hormone in a clonal pituitary gonadotrope cell line (alpha T3-1).
Stimulation of cultured pituitary cells from a gonadotrope lineage (alpha T3-1) by the gonadotropin-releasing hormone agonist analog [D-Trp6]GnRH (GnRH-A) resulted in a manifold increase in accumulation of phosphatidylethanol, a specific product of phospholipase D phosphatidyl transferase activity when ethanol is the phosphatidyl group acceptor. Levels of the natural lipid product of phospholipase D, phosphatidic acid, were increased 2-3-fold. Activation of phospholipase D by GnRH-A was dose- and time-dependent and was blocked by a GnRH receptor antagonist [D-pClPhe2,D-Trp3.6]GnRH. GnRH-A stimulated phospholipase D activity after a lag of 1-2 min. We conclude that in alpha T3-1 gonadotropes GnRH receptor occupancy results in delayed activation of phospholipase D which could participate in late phases of gonadotrope regulation by the neurohormone.
Netiv
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Department of Biochemistry, George S. Wise Faculty of Life Science, Tel Aviv University, Ramat Aviv, Israel.
Liscovitch
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M
Naor
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D000818:Animals; D002999:Clone Cells; D004789:Enzyme Activation; D020404:Glycerophospholipids; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D008822:Mice, Transgenic; D010712:Phosphatidic Acids / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism*; D010902:Pituitary Gland / Q000201:enzymology; D017329:Triptorelin Pamoate / Q000031:analogs & derivatives*
D020404:Glycerophospholipids; D010712:Phosphatidic Acids; C051521:phosphatidylethanol; D017329:Triptorelin Pamoate; C072339:LHRH, 4-ClPhe(2)-Trp(3,6)-; D007987:Gonadotropin-Releasing Hormone; C019176:Tryptal; D010739:Phospholipase D