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Platelet‐activating factor stimulates receptor‐mediated fromation of reactive oxygen intermediates in human monocytes
Author(s) -
Pustynnikov M. G.,
Porodenko N. V.,
Makarova O. V.,
Kozyukov A. V.,
Moskaleva E. Yu.,
Sokolovsky A. A.,
Severin E. S.
Publication year - 1991
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02536534
Subject(s) - stimulation , chemistry , receptor , platelet activating factor , dissociation constant , chemiluminescence , clinical chemistry , platelet , stereochemistry , biochemistry , endocrinology , chromatography , biology , immunology
Abstract Stimulation of production of reactive oxygen intermediates (ROI) was examined in human peripheral blood monocytes by luminol‐dependent chemiluminescence. The dose‐response cureve characterizing the dependence of ROI production on the concentration of platelet‐activating factor (PAF) showed that stimulation occurred within a concentration range of 2×10 −9 M to 5×10 −6 M. Transformation of the dose‐response curve to an Eadie‐Hofstee plot indicated that the process is characterized by two K m values. The K m value corresponding to the high‐affinity branch of the curve is 1.3±0.14 nM. In the same cells, the dissociation constant for the [ 3 H]PAF/receptor complex was determined. The K d value was 0.8±0.1 nM, which agreed quite well with the high‐affinity K m value obtained in the Eadie‐Hofstee plot. The data indicate that stimulation of ROI generation is mediated through PAF binding at specific receptor sites at nanomolar PAF concentrations. Along with the specific receptor‐mediated ROI generation, a nonspecific effect of PAF at a high concentration was demonstrated.