Epidermal growth factor stimulates hydrolysis of phosphatidylinositol 4,5-bisphosphate, generation of diacylglycerol and exocytosis in mouse spermatozoa.
Mouse spermatozoa stimulated with epidermal growth factor (EGF) or zona pellucida (ZP) experienced phosphatidylinositol 4,5-bisphosphate hydrolysis, diacylglycerol (DAG) generation and acrosomal exocytosis. The agonists showed additive effects but the action of EGF is likely to be mediated by a distinct receptor because maximal stimulation achieved with EGF was enhanced further by ZP. Generation of DAG and exocytosis stimulated by EGF were inhibited by tyrphostin A48, indicating that tyrosine kinase activity mediates EGF action. On the other hand, pertussis toxin did not affect the EGF-induced formation of DAG or exocytosis, ruling out the involvement of sperm Gi-like proteins. These results indicate that EGF could be an important co-factor in the initiation of exocytosis in spermatozoa.
Murase
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Department of Development and Signalling, Babraham Institute, Cambridge, UK.
Roldan
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D000177:Acrosome / Q000502:physiology; D000818:Animals; D004075:Diglycerides / Q000378:metabolism*; D004527:Egg Proteins / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005089:Exocytosis; D008297:Male; D008562:Membrane Glycoproteins / Q000494:pharmacology; D051379:Mice; D037342:Pertussis Toxin; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011956:Receptors, Cell Surface; D015398:Signal Transduction; D013094:Spermatozoa / Q000187:drug effects*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D000072216:Zona Pellucida Glycoproteins
D004075:Diglycerides; D004527:Egg Proteins; D008562:Membrane Glycoproteins; D018129:Phosphatidylinositol Phosphates; D011956:Receptors, Cell Surface; D010566:Virulence Factors, Bordetella; D000072216:Zona Pellucida Glycoproteins; D004815:Epidermal Growth Factor; D037342:Pertussis Toxin; D011505:Protein-Tyrosine Kinases