Two mechanisms of sulfate-S35 uptake by blood platelets of rats

Abstract

Labeling of blood platelets of rats with sulfate-S³⁵ was studied during the 32-hr period following a single injection of this isotope. A decline in platelet radioactivity during the first 12 hr followed by a rise was observed, indicating an early, short half-time labeling of circulating platelets and a less rapid appearance in the circulatory system of platelets labeled in the hemopoietic tissue. The compound that is labeled during the early period seems relatively labile, although its nature is not known. The label acquired by platelets during hemopoiesis is, at least in part, in the form of a sulfated mucopolysaccharide and appears to undergo little turnover in circulating platelets.