title: Arachidonic acid is involved in the regulation of hCG induced steroidogenesis in rat Leydig cells.
abstract: Phospholipase C (PLC), an enzyme involved in the hydrolysis of membrane phospholipid- phosphatidylinositol-bisphosphate to inositol triphosphate and diacylglycerol, and Phorbol 12, myristate 13, acetate (PMA), a tumor promoting agent, could significantly stimulate testosterone (T) secretion from Leydig cells. Arachidonic acid (AA) stimulated T secretion by about 2 fold. The steroidogenic effect of PLC and AA was biphasic. At low concentrations both PLC and AA (100 mU and 12.5 microM, respectively) augmented hCG induced T secretion, while at higher concentrations (PLC: 500 mU and AA: 200 microM) they inhibited steroid production. AA also had a biphasic effect on hCG induced cyclic AMP secretion. 5, 8, 11, 14 Eicosatetraynoic acid (ETYA), a general inhibitor of AA metabolism, and Nordihydroguaiaretic acid (NDGA), an inhibitor of the lipoxygenase pathway of AA metabolism, inhibited hCG induced T secretion while indomethacin, an inhibitor of cyclo-oxygenase pathway, had no effect on hCG induced T secretion. We conclude from these data that AA plays a role in the regulation of hCG induced steroidogenic responses in rat Leydig cells and that the metabolite(s) of AA that are involved are not cyclooxygenase products.
mesh_terms: D015117:5,8,11,14-Eicosatetraynoic Acid / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology*; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D066298:In Vitro Techniques; D007700:Kinetics; D007985:Leydig Cells / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009637:Masoprocol / Q000494:pharmacology; D051381:Rats; D013739:Testosterone / Q000096:biosynthesis* / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism / Q000494:pharmacology
chemical_list: D001095:Arachidonic Acids; D006063:Chorionic Gonadotropin; D015117:5,8,11,14-Eicosatetraynoic Acid; D016718:Arachidonic Acid; D013739:Testosterone; D009637:Masoprocol; D010738:Type C Phospholipases; D013755:Tetradecanoylphorbol Acetate