title: Half-life of platelet factor 4 (PF-4) in plasma and platelets from macaca mulatta.
abstract: Human platelet factor 4 (PF-4) showed a reaction of complete identity with PF-4 from Macaca mulatta when tested against rabbit anti-human-PF-4. Such immunoglobulin was used for quantitative precipitation of in vivo labelled PF-4 in monkey serum. The results suggest that the active protein had an intra-platelet half-life of about 21 hours. In vitro 125I-labelled human PF-4 was injected intravenously into two monkeys and isolated by immuno-precipitation from platelet-poor plasma and from platelets disrupted after gel-filtration. Plasma PF-4 was found to have a half-life of 7 to 11 hours. Some of the labelled PF-4 was associated with platelets and this fraction had a rapid initial disappearance rate and a subsequent half-life close to that of plasma PF-4. The results are compatible with the hypothesis that granular PF-4 belongs to a separate compartment, whereas membrane-bound PF-4 and plasma PF-4 may interchange.
mesh_terms: D000818:Animals; D001779:Blood Coagulation Factors / Q000032:analysis*; D006207:Half-Life; D000882:Haplorhini; D006801:Humans; D008251:Macaca / Q000097:blood*; D008253:Macaca mulatta / Q000097:blood*; D010978:Platelet Factor 4 / Q000032:analysis*; D011817:Rabbits / Q000097:blood
chemical_list: D001779:Blood Coagulation Factors; D010978:Platelet Factor 4