A comparative study of arachidonic acid metabolism in rabbit cultured astrocytes and human astrocytoma cells (1321N1).
1. ATP, bradykinin (BK), and A-23187 activated the generation of prostaglandin (PG) E2 and thromboxane (TX) B2 in rabbit astrocytes, but not in human astrocytoma cells (1321N1). 2. In human astrocytoma cells, ATP, BK, and A-23187 could not release [3H]arachidonic acid (AA) from [3H]AA-labeled cells and exogenous AA was not converted to TXB2 and PGE2, suggesting the lack of phospholipase (PL) A2 and cyclooxygenase activities in 1321N1 human astrocytoma cells, although they express TXA2 receptors. 3. In rabbit astrocytes, ATP and BK, but not A-23187, showed increased accumulation of inositol phosphates, indicating that an increase in intracellular Ca2+ concentration alone would not be enough to activate PLC. Furthermore, indomethacin, a cyclooxygenase inhibitor, partially attenuated ATP-induced phosphoinositide hydrolysis, indicating that cyclooxygenase product(s) would secondarily activate PLC in response to ATP.
Ishimoto
H
H
Department of Pharmacology, Fukushima Medical College, Japan.
Matsuoka
I
I
Nakanishi
H
H
Nakahata
N
N
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism* / Q000494:pharmacology; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001254:Astrocytoma / Q000378:metabolism*; D001920:Bradykinin / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D010716:Phosphatidylinositols / Q000096:biosynthesis; D011817:Rabbits; D014407:Tumor Cells, Cultured
D010716:Phosphatidylinositols; D016718:Arachidonic Acid; D000001:Calcimycin; D000255:Adenosine Triphosphate; D001920:Bradykinin