Mobilisation of arachidonic acid in human A431 cells in the presence of epidermal growth factor, calcium ions, and cyclic AMP.
Epidermal growth factor (EGF) at a concentration of 5 x 10(-11)-10(-8) M invoked mobilisation of arachidonate in cultured A431 human epidermal carcinoma cells and release of a certain proportion of free arachidonic acid and its derivatives into the growth medium. At a concentration of 2 x 10(-8)-4 x 10(-5) M, Ca2+ ions enhanced mobilisation of arachidonate and induced virtually total release of arachidonic acid and its derivatives into the medium. EGF at a concentration of 10(-8) M and Ca2+ ions at a concentration of 2 mM in the presence of calcium ionophore A23187 were found to have an additive effect on the release of arachidonic acid. Release of arachidonic acid by Ca2+ ions was inhibited by 30%-50% in the presence of 10(-4) M dibutyryl-cAMP (Bt2cAMP), isoproterenol, or noradrenaline. There was a 35%-55% increase in the release of arachidonate elicited by 10(-8) M EGF in the presence of 10(-4) M Bt2cAMP, noradrenaline, or isoproterenol. It is concluded that A431 cells contain two independent pathways for the mobilisation of arachidonic acid: a Ca(2+)-dependent pathway and an EGF-dependent pathway.
Kudryavtseva
N G
NG
Department of Biochemistry, Faculty of Biology, Moscow State University.
Popov
K M
KM
Bulargina
T V
TV
D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D001095:Arachidonic Acids; D016718:Arachidonic Acid; D000001:Calcimycin; D004815:Epidermal Growth Factor; D003994:Bucladesine; D000242:Cyclic AMP; D007545:Isoproterenol; D002118:Calcium; D009638:Norepinephrine