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Determination of basal and stimulated levels of inositol triphosphate in (/sup 32/P)orthophosphate-labeled platelets

Journal Article · · Anal. Biochem.; (United States)
Previous studies indicated that thrombin-stimulation of platelets prelabeled with (/sup 3/H)inositol or (/sup 32/P)orthophosphate results in an increase of radioactive inositol triphosphate, a substance thought to modulate the levels of free intracellular calcium. In the present study, we improved the method of resolution of inositol triphosphate from other compounds that are also labeled with (/sup 32/P)orthophosphate using a combination of enzyme treatment and electrophoresis. We have further demonstrated that the specific activities of metabolic ATP and phosphatidylinositol diphosphate (the precursor of inositol triphosphate) are identical in (/sup 32/P)orthophosphate-labeled platelets. It follows that the amount of inositol triphosphate is proportional to its radioactivity in the metabolic compartment of the cells. Using this protocol, the concentration of inositol triphosphate in resting and thrombin-stimulated platelets were determined to be 1-4 and 10-30 pmol/10/sup 8/ cells, respectively.
Research Organization:
Temple Univ., Philadelphia, PA
OSTI ID:
5578678
Journal Information:
Anal. Biochem.; (United States), Journal Name: Anal. Biochem.; (United States) Vol. 154:2; ISSN ANBCA
Country of Publication:
United States
Language:
English