Luteinizing hormone-releasing hormone enhances polyphosphoinositide breakdown in rat granulosa cells.
A 2-min addition of LHRH to [3H]inositol-prelabeled rat granulosa cells in primary culture evoked significant increases in the accumulation of [3H]inositol phosphates, i.e. radiolabeled inositol monophosphate (IP), inositol diphosphate (IP2), and inositol triphosphate (IP3) levels increased to 210, 590 and 520%, respectively, when compared to control cultures. By contrast, addition of FSH failed to elicit such a response. The effect of LHRH was completely blocked by the concomitant presence of a specific LHRH antagonist. LHRH evoked increase in [3H]IP3 and [3H]IP2 accumulation as early as 30 sec, while the increase in [3H]IP became significant at 2 min. These data support the hypothesis that polyphosphoinositide breakdown may be an early step in the intracellular signal mechanism which mediates the action of LHRH.
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D000818:Animals; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000494:pharmacology*; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D007294:Inositol / Q000378:metabolism; D007700:Kinetics; D010716:Phosphatidylinositols / Q000378:metabolism*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D051381:Rats; D011919:Rats, Inbred Strains
D010716:Phosphatidylinositols; D007987:Gonadotropin-Releasing Hormone; D007294:Inositol; C034511:LHRH, pGlu(1)-Phe(2)-Trp(3,6)-; D005640:Follicle Stimulating Hormone; D011761:Pyrrolidonecarboxylic Acid