Canine Cyclic Hematopoiesis: Platelet Size and Thrombopoietin Level in Relation to Platelet Count

Platelet size, platelet count, and thrombopoietin levels in plasma fractions were determined in cyclic hemato-poietic (CH) dogs. Results show that platelet sizes varied inversely with platelet counts of CH dogs; significantly elevated levels of thrombopoietin were found in fractions of plasma from CH dogs at the beginning of active thrombopoiesis. These dogs serve as a useful model for studying cycling thrombopoiesis in man.