EGF modulates phosphoinositide levels in ovarian granulosa cells stimulated by luteinizing hormone.
Hamster granulosa cells were exposed to epidermal growth factor (EGF) and luteinizing hormone (LH) to study cross-talk between second messenger pathways involving tyrosine kinase, cAMP, and phosphoinositides. Granulosa cells from ovarian preovulatory follicles of PMSG-primed hamsters were incubated with various additives in serum-free medium. LH, but not EGF, stimulated inositol phosphate (IP) accumulation; however, when combined with LH, EGF inhibited IP accumulation in a manner that was concentration dependent for both LH and EGF. The inhibitory effects of EGF were significantly reduced by the tyrosine kinase inhibitor genistein and by pertussis toxin suggesting a role for tyrosine kinase and an inhibitory G-protein (Gi) in this system. EGF stimulated an increase in cAMP, but it does not appear to modulate LH-stimulated IP levels via cAMP.
Hubbard
C J
CJ
Department of Biological Sciences, Northern Illinois University, DeKalb 60115.
D000818:Animals; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism*; D005260:Female; D019833:Genistein; D006107:Granulosa Cells / Q000378:metabolism*; D007295:Inositol Phosphates / Q000378:metabolism; D007529:Isoflavones / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000502:physiology*; D008647:Mesocricetus; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015290:Second Messenger Systems; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D007295:Inositol Phosphates; D007529:Isoflavones; D010716:Phosphatidylinositols; D010566:Virulence Factors, Bordetella; D004815:Epidermal Growth Factor; D007986:Luteinizing Hormone; D019833:Genistein; D000242:Cyclic AMP; D037342:Pertussis Toxin; D011505:Protein-Tyrosine Kinases