Heparin inhibits the inositol 1,4,5‐trisphosphate‐induced Ca2+ release from rat liver microsomes

Abstract
Inositol 1,4,5‐trisphosphate (Ins (1,4,5)P3)‐stimulated Ca2+ release is inhibited by low concentrations of heparin (IC50=4.5 μg/ml). GTP‐stimulated Ca2+ release is unaffected at a heparin concentration of 16 μ/ml. Addition of heparin after Ins (1,4,5)P3 causes the rapid re‐uptake of Ins (1,4,5)P3‐releasable Ca2+.
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