Effect of thromboxane antagonists on prostaglandin regulation of platelet adenylate cyclase. 1988

B Ashby
Thrombosis Research Center, University Health Sciences Center, Philadelphia, PA 19140.

Platelet adenylate cyclase appears to be regulated through separate stimulatory and inhibitory prostaglandin receptors. To test the possibility that the inhibitory receptor represents overlap with a thromboxane A2 receptor the effect of thromboxane antagonists on prostaglandin regulation of adenylate cyclase was examined. Neither 13-azaprostanoic acid nor SQ29,548 had any effect on prostaglandin-mediated cyclic AMP regulation in intact platelets, while pinane thromboxane A2 and carbocyclic thromboxane A2 exhibited behavior consistent with these compounds acting as agonists at the inhibitory prostaglandin site. Because of the divergent behavior of the two groups of thromboxane antagonists it is unclear whether the inhibitory prostaglandin site represents a thromboxane site. It seems clear, however, that PTA2 and CTA2 represent pure agonists at the prostaglandin inhibitory site, showing little, if any, overlap with the stimulatory site, and therefore represent useful compounds for the study of prostaglandin regulation of platelet adenylate cyclase, providing additional evidence for the existence of a distinct prostaglandin inhibitory site.

UI MeSH Term Description Entries
D011464 Epoprostenol A prostaglandin that is a powerful vasodilator and inhibits platelet aggregation. It is biosynthesized enzymatically from PROSTAGLANDIN ENDOPEROXIDES in human vascular tissue. The sodium salt has been also used to treat primary pulmonary hypertension (HYPERTENSION, PULMONARY). Prostacyclin,Prostaglandin I2,Epoprostanol,Epoprostenol Sodium,Epoprostenol Sodium Salt, (5Z,9alpha,11alpha,13E,15S)-Isomer,Flolan,Prostaglandin I(2),Veletri
D011982 Receptors, Prostaglandin Cell surface receptors that bind prostaglandins with high affinity and trigger intracellular changes which influence the behavior of cells. Prostaglandin receptor subtypes have been tentatively named according to their relative affinities for the endogenous prostaglandins. They include those which prefer prostaglandin D2 (DP receptors), prostaglandin E2 (EP1, EP2, and EP3 receptors), prostaglandin F2-alpha (FP receptors), and prostacyclin (IP receptors). Prostaglandin Receptors,Prostaglandin Receptor,Receptor, Prostaglandin,Receptors, Prostaglandins,Prostaglandins Receptors
D001792 Blood Platelets Non-nucleated disk-shaped cells formed in the megakaryocyte and found in the blood of all mammals. They are mainly involved in blood coagulation. Platelets,Thrombocytes,Blood Platelet,Platelet,Platelet, Blood,Platelets, Blood,Thrombocyte
D004305 Dose-Response Relationship, Drug The relationship between the dose of an administered drug and the response of the organism to the drug. Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D004347 Drug Interactions The action of a drug that may affect the activity, metabolism, or toxicity of another drug. Drug Interaction,Interaction, Drug,Interactions, Drug
D000067956 Adenylyl Cyclase Inhibitors Compounds that bind to and inhibit the action of ADENYLYL CYCLASES. Adenylate Cyclase Inhibitors,Cyclase Inhibitors, Adenylate,Cyclase Inhibitors, Adenylyl,Inhibitors, Adenylate Cyclase,Inhibitors, Adenylyl Cyclase
D000081008 Bicyclic Monoterpenes Monoterpenes containing two ring structures that are joined either by bridgehead carbon atoms or fused ring structure. Camphene Derivatives,Camphenes,Carane Derivatives,Caranes,Pinane Derivatives,Pinanes,Thujane Derivatives,Thujanes,Derivatives, Camphene,Derivatives, Carane,Derivatives, Pinane,Derivatives, Thujane,Monoterpenes, Bicyclic
D000242 Cyclic AMP An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH. Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
D000262 Adenylyl Cyclases Enzymes of the lyase class that catalyze the formation of CYCLIC AMP and pyrophosphate from ATP. Adenyl Cyclase,Adenylate Cyclase,3',5'-cyclic AMP Synthetase,Adenylyl Cyclase,3',5' cyclic AMP Synthetase,AMP Synthetase, 3',5'-cyclic,Cyclase, Adenyl,Cyclase, Adenylate,Cyclase, Adenylyl,Cyclases, Adenylyl,Synthetase, 3',5'-cyclic AMP
D001665 Binding Sites The parts of a macromolecule that directly participate in its specific combination with another molecule. Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
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