Isolation and characterization of 9-hydroxy-10-trans,12-cis-octadecadienoic acid, a novel regulator of platelet adenylate cyclase from Glechoma hederacea L. Labiatae.
We have identified and characterized a fatty acid, (9S,10E,12Z)-9-hydroxy-10,12-octadecadienoic acid (9-HODE) as a regulator of adenylate cyclase activity of human platelet membranes. This fatty acid was isolated from a methanolic extract of the plant Glechoma hederacea L. Labiatae (commonly known as 'lierre terrestre', 'ground ivy' or 'creeping Charlie'; it was identified by nuclear magnetic resonance and mass spectroscopy. This compound increased basal adenylate cyclase activity in platelet membranes about threefold and had an EC50 of 10-20 microM. This increase in adenylate cyclase activity occurred without a temporal lag, was reversible, and represented an increase in Vmax without a substantial change in Km for ATP, Mg2+ or Mn2+. In addition, 9-HODE additively or synergistically increased platelet adenylate cyclase activity in response to guanosine 5'-[beta,gamma-imido]triphosphate and forskolin, but the fatty acid failed to alter inhibition of adenylate cyclase activity mediated by epinephrine (alpha 2-adrenergic receptor). Studies of the interaction of 9-HODE with activation of platelet adenylate cyclase activity mediated by prostaglandin E1 (PGE1) and prostaglandin D2 (PGD2) indicated that this fatty acid produced a parallel shift in the concentration/response curve of PGE1 and PGD2 without altering maximal response, which was substantially greater than that observed with 9-HODE alone. From these results, we conclude that 9-HODE appears to be a partial agonist at PGE1 and PGD2 receptors on human platelets. We believe that this is a novel example of a plant-derived fatty acid which acts on cells to regulate adenylate cyclase via prostaglandin receptors.
Henry
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Unité de Recherche Institut National de la Santé et de la Recherche Médicale Unité 99, Hôpital Henri Mondor, Creteil, France.
Gueritte-Voegelein
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F
Insel
P A
PA
Ferry
N
N
Bouguet
J
J
Potier
P
P
Sevenet
T
T
Hanoune
J
J
D000262:Adenylyl Cyclases / Q000097:blood*; D001792:Blood Platelets / Q000201:enzymology*; D006801:Humans; D007700:Kinetics; D008041:Linoleic Acids / Q000302:isolation & purification* / Q000494:pharmacology; D044243:Linoleic Acids, Conjugated; D010944:Plants / Q000032:analysis*; D010974:Platelet Aggregation / Q000187:drug effects
D008041:Linoleic Acids; D044243:Linoleic Acids, Conjugated; C024347:9-hydroxy-10,12-octadecadienoic acid; D000262:Adenylyl Cyclases