Arachidonic acid metabolism in murine lymphoma cell sublines differing in radiation sensitivity.
14C arachidonic acid incorporation and 14C radioactivity release as well as prostaglandin (PG) and 5-hydroxyeicosatetraenoic acid (5-HETE) synthesis were measured in the pair of murine lymphoma L5178Y (LY) cell sublines differing in radiation sensitivity. Both LY sublines, LY-R (resistant) and LY-S (sensitive), incorporated exogenous arachidonic acid and released it from membrane phospholipids. Ca2+ ionophores (ionomycin and A23187) but not PMA stimulated the liberation of 14C arachidonic acid in LY cells. PMA did not potentiate the 14C arachidonic acid release both in the presence or in the absence of A23187; this observation suggests that protein kinase C activation is not essential for the regulation of arachidonic acid release by LY-R and LY-S cells. X-irradiation (5 Gy) did not change the uptake of 14C arachidonic acid into LY-R and LY-S cells and did not potentiate the release of its total radioactivity from the cells. PG synthesis was stimulated in irradiated LY-R cells but not in LY-S cells. The susceptibility of eicosanoid metabolism to A23187 and H2O2 was altered in irradiated LY-R cells. A23187 stimulated only PG and 5-HETE synthesis in irradiated LY-R cells. H2O2 did not stimulate the synthesis of PG from exogenous arachidonic acid in irradiated LY-R and LY-S cells and 5-HETE synthesis in LY-R cells. An implication of the increased PG synthesis in LY-R cells in the protection against radiation is discussed.
Sochanowicz
B
B
Department of Radiobiology, Institute of Nuclear Chemistry and Technology, Warszawa, Poland.
Szumiel
I
I
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D002460:Cell Line; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis; D015759:Ionomycin / Q000494:pharmacology; D008223:Lymphoma / Q000378:metabolism*; D051379:Mice; D010743:Phospholipids / Q000378:metabolism; D011453:Prostaglandins / Q000096:biosynthesis; D011836:Radiation Tolerance / Q000502:physiology*; D019311:Staurosporine / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014965:X-Rays
D006893:Hydroxyeicosatetraenoic Acids; D010743:Phospholipids; D011453:Prostaglandins; D016718:Arachidonic Acid; D000001:Calcimycin; C022022:5-hydroxy-6,8,11,14-eicosatetraenoic acid; D015759:Ionomycin; D006861:Hydrogen Peroxide; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate