Kinetic analysis of alpha-granule secretion by platelets. A methodological report.

A method is described for the kinetic measurement of alpha-granule secretion by platelets. The method uses formaldehyde as a secretion-blocking reagent. This treatment alters the antigenecity of beta-thromboglobulin but not of Platelet Factor 4, both measured with commercially available reagents. Evidence is shown that this formaldehyde effect does not alter the secretion kinetics when the data are expressed as a percentage of a similarly treated reference sample. The method shows that following stimulation with thrombin or A 23187 alpha-granule secretion is much slower than dense granule secretion.