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Studies on murine embryo‐derived platelet‐activating factor (EPAF)
Author(s) -
Adamson L. M.,
Podsiadly B.,
Smart Y. C.,
Stanger J. D.,
Roberts T. K.
Publication year - 1991
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080300307
Subject(s) - platelet activating factor , embryo , platelet , biology , in vitro , platelet rich plasma , microbiology and biotechnology , biological activity , biochemistry , andrology , immunology , medicine
Abstract Studies were carried out using the splenectomized mouse bioassay (SMB) to investigate the nature of embryo‐derived platelet‐activating factor (EPAF) and its relationship to synthetic platelet activating factor (PAF). While both C16‐PAF and embryo conditioned media (ECM) induced a significant platelet decline in the SMB at 15 min postinjection, C18‐PAF induced a similar effect at 30 min postinjection. The degree of EPAF activity in ECM was not altered with increasing embryo number from 2 to 40/ml of media. In contrast, PAF (C16/C18 mixture) induced a linear increase in activity with increasing concentration, leading to lethal effects at high concentrations. While EPAF activity was not significantly altered when ECM was diluted 1/1,000, PAF activity was abolished at 1/10 dilution. EPAF in ECM was not inactivated by mouse plasma; however, lipid exracted ECM, like PAF, underwent rapid inactivation in the presence of plasma. Aggregometer studies using horse platelets showed that ECM and lipid‐extracted ECM were unable to induce platelet aggregation, while thin‐layer chromatography (TLC) purified ECM (Rf 0.23) successfully aggregated horse platelets in vitro. Results suggested that EPAF and PAF are not homologous. EPAF might consist of PAF bound to a regulatory carrier molecule and appears to be associated with EPAF‐inhibitor substance(s) in ECM.