Specificity of inositol phosphate-stimulated Ca2+ mobilization from Swiss-mouse 3T3 cells.
Pure samples of inositol 1,3,4-trisphosphate, inositol 1,3,4,5-tetrakisphosphate and inositol 1,2-cyclic 4,5-trisphosphate were prepared and tested for their ability to mobilize calcium from intracellular stores in a permeabilized Swiss mouse 3T3 cell preparation. In this system inositol 1,4,5-trisphosphate mobilizes Ca2+ with a half-maximal dose of 0.3 microM. Inositol 1,2-cyclic 4,5-trisphosphate mobilized Ca2+ to the same extent with a half-maximal dose of 0.3 microM, whereas inositol 1,3,4-trisphosphate required a half-maximal dose of approx. 9 microM to give the same effect. Inositol 1,3,4,5-tetrakisphosphate was ineffective up to 20 microM and at that concentration did not antagonize the mobilization induced by inositol 1,4,5-trisphosphate. The relevance of these findings to the function of the inositol tris/tetrakis-phosphate pathway is discussed.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D007295:Inositol Phosphates / Q000494:pharmacology*; D051379:Mice; D008815:Mice, Inbred Strains; D013403:Sugar Phosphates / Q000494:pharmacology*
D007295:Inositol Phosphates; D013403:Sugar Phosphates; D002118:Calcium