On the Active Principles in Toh’s Alkaline Tissue Extracts Which Cause Release of Serotonin from Blood Platelets
The release of serotonin from rabbit blood platelets by the alkaline extracts of tissue, originally described by Toh in 1956, was re-examined. The extracts were found not only to cause the release of serotonin on incubation with platelets, but also to inhibit strongly the uptake into platelets of the amine added to the incubation medium. Hardly any apparent damage of platelets was, however, caused by the extracts. The activity of the extracts was dependent on temperature and varied with the tissue used. Extracts of kidney showed the greatest activity. Moreover, the activity was inhibited by the presence of glucose in the incubation medium but remained unaffected after pretreatment with trypsin and chymotrypsin.
Based on these results, partial purification and chemical characterization of active principles in the alkaline kidney extract was attempted using extraction with organic solvents and thin-layer chromatography. The results obtained strongly suggest that the active principles are of acidic lipid nature and it is highly probable that they are mono- and di-enoic fatty acids set free by the alkali treatment used for tissue extraction. Such a view was supported by a model experiment in which authentic oleic and linoleic acid could liberate platelet serotonin on incubation but stearic and linolenic acid failed to do so.
Key-WordsSerotonin Release Platelets Alkaline Tissue Extract Unsaturated Fatty Acid Oleic Acid
SchlüsselwörterSeretonin-Befreiung Blutplättchen Alkalisches Gewebsextrakt Ungesättigte Fettsäuren Oleinsäure
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