Evidence for the formation of inositol 4-monophosphate in stimulated human platelets.
Human platelets were prelabeled with [3H] inositol and exposed to thrombin or vasopressin. The radioactive inositol monophosphates were separated by high-performance liquid chromatography and identified by cochromatography with unlabeled standard substances. Radioactive inositol 1-monophosphate (Ins 1-P) and inositol 4-monophosphate (Ins 4-P) were detected in unstimulated platelets and accumulated in response to thrombin or vasopressin. Ins 4-P as well as Ins 1-P increased after the formation of inositol 1,4-bisphosphate (Ins 1,4-P2) and inositol 1,4,5-trisphosphate (Ins 1,4,5-P3). Lithium augmented the accumulation of Ins 1-P and Ins 1,4-P2 in stimulated platelets, and also of Ins 4-P in platelets stimulated by vasopressin, but not by thrombin. The results indicate that Ins 1,4-P2 formed in stimulated platelets is partly degraded to Ins 4-P. The significance of Ins 4-P as a marker molecule for the study of inositol phosphate metabolism in stimulated cells is discussed.
D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007294:Inositol / Q000097:blood; D007295:Inositol Phosphates / Q000097:blood*; D007700:Kinetics; D008094:Lithium / Q000494:pharmacology; D013403:Sugar Phosphates / Q000097:blood*; D013917:Thrombin / Q000494:pharmacology*; D014667:Vasopressins / Q000494:pharmacology*
D007295:Inositol Phosphates; D013403:Sugar Phosphates; D014667:Vasopressins; C045537:inositol 4-phosphate; D007294:Inositol; D008094:Lithium; D013917:Thrombin