Inositol cyclic triphosphate [inositol 1,2-(cyclic)-4,5-triphosphate] is formed upon thrombin stimulation of human platelets.
Cleavage of polyphosphoinositides in vitro by phospholipase C results in formation of both cyclic and noncyclic inositol phosphates. We have now isolated the cyclic product of phosphatidylinositol 4,5-bisphosphate cleavage, inositol 1,2(cyclic)-4,5-triphosphate [cIns(1:2,4,5)P3], from thrombin-treated platelets. We found 0.2-0.4 nmol of cIns-(1:2,4,5)P3 per 10(9) platelets at 10 sec after thrombin; none was found in unstimulated platelets or in platelets 10 min after thrombin addition. We conclude that cIns(1:2,4,5)P3 is a major product of polyphosphoinositide metabolism in thrombin-stimulated platelets.
D001792:Blood Platelets / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007295:Inositol Phosphates / Q000097:blood*; D010716:Phosphatidylinositols / Q000097:blood*; D013403:Sugar Phosphates / Q000097:blood*; D013917:Thrombin / Q000378:metabolism*
D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D013403:Sugar Phosphates; C049924:inositol-1,2-cyclic-4,5-triphosphate; D013917:Thrombin