DETERMINATION OF HUMAN PLATELET SURVIVAL UTILIZING C(14)-LABELED SEROTONIN

All of the methods available for estimation of platelet survival have certain disadvantages. Iso-lation and considerable manipulation of platelets in vitro are necessary with the Cr51 technique (1, 2). The p32 (3), diisopropylfluorophosphate32 (DFP32) (4), or S35 (5) methods are all in vivo labeling procedures. Studies with p32 or S35 re-quire special subjects for study (patients with polycythemia vera or leukemia). Finally, both autologous and homologous platelet survival can-not be studied with facility. The use of serotonin [5-hydroxytryptamine (5-HTA)] as a platelet label appeared to have cer-tain advantages. It is preferentially concentrated by blood platelets in vivo and in vitro (6). Iso-lation of platelets is not required to achieve an in vitro label, and in vivo labeling of platelets can be accomplished without labeling their precursors. We have used radioactive labeled (C14) serotonin to study platelet survival