title: Clearance and in vivo release by heparin of human platelet factor 4 (PF4) in the rabbit.
abstract: 13 male New Zealand rabbits were injected with two different doses (25 micrograms/Kg and 100 micrograms/Kg) of human platelet factor 4 antigen (PF4). The disappearance of the protein was extremely fast with an half-life for the fast component of 1.07 +/- 0.16 and 1.76 +/- 0.11 min respectively. The half-life for the slow component, detectable only with the highest dosage, was 18.8 min. The administration of 2500 I.U. of heparin 30 min after PF4 administration induced a partial release of the injected protein and its clearance from plasma was slow, with half-life of 23.3 +/- 5.9 min and 30.9 +/- 2.19 min respectively.
mesh_terms: D000818:Animals; D000941:Antigens / Q000032:analysis; D006207:Half-Life; D006493:Heparin / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D008297:Male; D010978:Platelet Factor 4 / Q000276:immunology / Q000302:isolation & purification; D011817:Rabbits; D011863:Radioimmunoassay
chemical_list: D000941:Antigens; D010978:Platelet Factor 4; D006493:Heparin