title: Failure to detect platelet-activating factor using the splenectomized mouse bioassay.
abstract: The ability of purified preparations of platelet-activating factor (PAF), from three different suppliers, to induce thrombocytopaenia in mice after splenectomy and to activate mouse platelets in vitro was examined. Although the PAF preparations were potent activators of horse and cow platelets in vitro, injections of up to 1 microgram PAF failed to elicit thrombocytopaenia responses in either CD1 or Swiss Webster random-bred mice. However, when thrombin was injected into Swiss Webster mice, a dose-dependent decrease in the concentration of platelets was observed. Furthermore, isolated platelets from these strains and from 3 inbred lines (C3H/He, BALB/c, C57BL/6) of mice, were not aggregated by PAF in vitro but were sensitive to adenosine diphosphate and thrombin. No change in circulating platelet concentrations was observed over the initial 7 days of gestation in intact Swiss Webster and C57BL/6 or splenectomized C57BL/6 mice, suggesting either an absence of PAF production during early pregnancy in these strains or insensitivity of their platelets to PAF. These results suggest that many mouse strains are unsuitable for the bioassay of PAF.
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Canada.
authors.forename: J M
authors.initials: JM
authors.lastname: Scodras
authors.forename: K J
authors.initials: KJ
authors.lastname: Betteridge
authors.forename: B A
authors.initials: BA
authors.lastname: Croy
authors.forename: I B
authors.initials: IB
authors.lastname: Johnstone
authors.forename: D
authors.initials: D
authors.lastname: Rieger
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D001681:Biological Assay / Q000379:methods*; D001792:Blood Platelets / Q000187:drug effects; D002417:Cattle; D006736:Horses; D051379:Mice; D008815:Mice, Inbred Strains; D010972:Platelet Activating Factor / Q000032:analysis* / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects; D010976:Platelet Count / Q000187:drug effects; D013156:Splenectomy; D013917:Thrombin / Q000494:pharmacology; D013921:Thrombocytopenia / Q000139:chemically induced
chemical_list: D010972:Platelet Activating Factor; D000244:Adenosine Diphosphate; D013917:Thrombin