Glucocorticosteroids and in vitro effects on chemiluminescence of isolated bovine blood granulocytes.
The effects of glucocorticosteroids on respiratory burst of bovine granulocytes were studied in vitro by means of (1) chemiluminescence (luminol-dependent, phorbol 12-myristate 13-acetate (PMA)-stimulated), (2) a cell-free chemiluminescence assay, and (3) a myeloperoxidase assay. Significant effects on cellular chemiluminescence were only observed at the highest, not obtainable in vivo, concentration for all drugs except betamethasone. Prednisolone induced inhibition at therapeutic doses. Also, flumethasone and dexamethasone induced significant inhibition at lower concentrations. In the cell-free assay, all glucocorticosteroids, except betamethasone, inhibited chemiluminescence at high concentrations. None of the glucocorticosteroids tested affected myeloperoxidase activity. The results indicated that the drugs do not affect NADPH-oxidase activity. The adverse effects may be due to scavenging of free oxygen radicals, or to interference with the interaction between luminol and the myeloperoxidase-H2O2-halide system. It can be concluded that most glucocorticosteroids show no adverse effects on the respiratory burst of bovine granulocytes in vitro at therapeutical concentrations.
Hoeben
D
D
Department of Physiology, Biochemistry and Biometrics, University of Ghent, Faculty of Veterinary Medicine, Merelbeke, Belgium. dagmar.hoeben@rug.ac.be
Burvenich
C
C
Massart-Leën
A M
AM
D000818:Animals; D002417:Cattle; D002474:Cell-Free System / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005938:Glucocorticoids / Q000494:pharmacology; D008163:Luminescent Measurements; D009504:Neutrophils / Q000187:drug effects* / Q000502:physiology; D009195:Peroxidase / Q000037:antagonists & inhibitors / Q000378:metabolism; D016897:Respiratory Burst / Q000187:drug effects; D013256:Steroids / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D005938:Glucocorticoids; D013256:Steroids; D009195:Peroxidase; D013755:Tetradecanoylphorbol Acetate