Effects of epidermal growth factor on isolated digestive gland cells from mussels.
Effects of epidermal growth factor (EGF) and possible mechanisms of EGF-mediated signal transduction were investigated in isolated cells of the digestive gland of the mussel (Mytilus galloprovincialis Lam. ). EGF induced a cytosolic Ca2+ transient and subsequently stimulated DNA synthesis; both effects were dose-dependent in the nanomolar range and inhibited by pretreatment with an inhibitor of tyrosine kinase activity, suggesting specific EGFR-like receptors. The EGF-induced cytosolic Ca2+ transient was mainly due to a Ca2+ influx through the plasma membrane, possibly involving voltage-insensitive Ca2+ channels. Such a Ca2+ response was abolished by pretreatment with indomethacin and NDGA, inhibitors of arachidonic acid metabolism; similarly, the EGF-stimulated increase in DNA synthesis was significantly reduced. Indomethacin, a cyclooxygenase inhibitor, had the greatest effect on both EGF-induced responses. Results suggest the presence of EGF-responsive cells in the mussel digestive gland. A possible role for arachidonic acid and its metabolites in mediating the effects of EGF is also indicated.
Canesi
L
L
Istituto di Anatomia e Fisiologia, Università di Urbino, Via Budassi 28, Urbino, PS, 61029, Italy.
Ciacci
C
C
Orunesu
M
M
Gallo
G
G
D000818:Animals; D016718:Arachidonic Acid / Q000037:antagonists & inhibitors / Q000378:metabolism; D049872:Bivalvia / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000502:physiology; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D004064:Digestive System / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D007213:Indomethacin / Q000494:pharmacology; D007700:Kinetics; D009637:Masoprocol / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D015398:Signal Transduction
D015220:Calcium Channels; D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D016718:Arachidonic Acid; D004815:Epidermal Growth Factor; D009637:Masoprocol; D004247:DNA; D011505:Protein-Tyrosine Kinases; D002118:Calcium; D007213:Indomethacin