| Secretory mechanisms. Behaviour of adenine nucleotides during the platelet release reaction induced by adenosine diphosphate and adrenaline. | |
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MedLine Citation:
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PMID: 4675006 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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1. Platelets containing adenine nucleotides labelled with (3)H and (14)C in vitro were aggregated biphasically with ADP and adrenaline. Amounts of ATP and ADP as well as the radioactivity of ATP, ADP, AMP, IMP, hypoxanthine and adenine were determined in platelets and plasma at different stages of aggregation. 2. ATP and ADP were released during the second aggregation phase and had a low specific radioactivity compared with the ATP and ADP retained by the cells. The specific radioactivity of intracellular nucleotides increased during release. The parameters observed with ADP and adrenaline as release inducers were the same as for collagen and thrombin. 3. Release induced by all four inducers was accompanied by conversion of cellular [(3)H]ATP into extracellular [(3)H]-hypoxanthine. By variation of temperature, inducer concentration, time after blood withdrawal and use of acetylsalicylic acid, the aggregation pattern caused by adrenaline and ADP could be made mono- or bi-phasic. Release or second-phase aggregation was intimately connected with the ATP-hypoxanthine conversion, whereas first phase aggregation was not. 4. The [(3)H]ATP-hypoxanthine conversion started immediately after ADP addition. With adrenaline it usually started with the appearance of the second aggregation phase. The conversion was present during first phase of ADP-induced aggregation only if a second phase were to follow. 5. When secondary aggregation took place while radioactive adenine was being taken up by the platelets, increased formation of labelled hypoxanthine still occurred, but there was either no change or an increase in the concentration of labelled ATP. 6. Biphasically aggregated platelets converted [(3)H]adenine more rapidly into [(3)H]-ATP and -hypoxanthine than non-aggregated platelets. Addition of [(3)H]adenine at different stages of biphasic aggregation showed that more [(3)H]hypoxanthine was formed during than after the release step. 7. We conclude that ADP and adrenaline, like thrombin and collagen, cause extrusion of non-metabolic granula-located platelet adenine nucleotides. During release metabolic ATP breaks down to hypoxanthine, and this process might reflect an ATP-requiring part of the release reaction. |
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Authors:
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H Holmsen; H J Day; C A Setkowsky |
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Publication Detail:
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Type: In Vitro; Journal Article |
Journal Detail:
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Title: The Biochemical journal Volume: 129 ISSN: 0264-6021 ISO Abbreviation: Biochem. J. Publication Date: 1972 Aug |
Date Detail:
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Created Date: 1973-03-08 Completed Date: 1973-03-08 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 2984726R Medline TA: Biochem J Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 67-82 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adenine Adenine Nucleotides / metabolism* Adenosine Diphosphate / pharmacology* Adenosine Monophosphate / metabolism Adenosine Triphosphate / metabolism Animals Aspirin Blood Coagulation Blood Platelets / drug effects*, metabolism Carbon Isotopes Cattle Collagen Epinephrine / pharmacology* Glycolysis Horses Humans Hypoxanthines Inosine Nucleotides Oxidative Phosphorylation Thrombin Tritium |
| Chemical | |
Reg. No./Substance:
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0/Adenine Nucleotides; 0/Carbon Isotopes; 0/Hypoxanthines; 0/Inosine Nucleotides; 10028-17-8/Tritium; 50-78-2/Aspirin; 51-43-4/Epinephrine; 56-65-5/Adenosine Triphosphate; 58-64-0/Adenosine Diphosphate; 61-19-8/Adenosine Monophosphate; 73-24-5/Adenine; 9007-34-5/Collagen; EC 3.4.21.5/Thrombin |
| Comments/Corrections | |
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