calcimycin and benoxaprofen

Erythromycin and especially roxithromycin (1.25-20 micrograms/mL) stimulated neutrophil migration in vitro. Both antibiotics selectively inhibited superoxide generation by neutrophils activated with the N-formylated leukotactic tripeptide FMLP, the calcium ionophore A23187 and the pharmacologic agent benoxaprofen, while the responses initiated by the tumor promotor PMA and opsonized zymosan were unaffected. Neutrophil autooxidation during exposure to FMLP was also decreased by both antibiotics. The antimicrobial agents did not scavenge superoxide. Likewise, the interactions of [3H]FMLP with specific receptors on neutrophils, FMLP-activated degranulation and intracellular calcium fluxes, the activity of cytosolic protein kinase C and the release of [3H]arachidonate from calcium ionophore-stimulated neutrophils were all unaffected by the antibiotics. Erythromycin and roxithromycin in particular appear to enhance neutrophil migration by an antioxidant mechanism that is not due to inhibition of transductional events involved in the activation of NADPH-oxidase or to oxidant scavenging properties.

Topics: Calcimycin; Cell Movement; Erythromycin; Humans; In Vitro Techniques; Leucomycins; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Oxidation-Reduction; Propionates; Superoxides; Tetradecanoylphorbol Acetate; Zymosan

1. The effect of orpanoxin, a nonsteroidal anti-inflammatory drug, on cyclo-oxygenase and lipoxygenase activity in human polymorphonuclear leucocytes (PMNL) and platelets was studied ex vivo to see if lipoxygenase inhibition contributed to orpanoxin's mechanism of action. 2. In PMNL, orpanoxin (50, 100, and 200 mumols/l), like indomethacin (100 mumols/l), had little effect on synthesis of leukotriene B4 or 5S-hydroxy-6-trans,8,11,14-cis-eicosatetraenoic acid. BW755c at 100 mumols/l inhibited synthesis of both. 3. In PLT, orpanoxin (100 mumols/l) inhibited formation of cyclo-oxygenase products (thromboxanes, prostaglandins, and 12-L-hydroxy-5,8,10-heptadecatrienoic acid) and increased synthesis of the lipoxygenase product, 12S-hydroxy-5,8-cis,10-trans,14-cis-eicosatetraenoic acid. Effects of indomethacin (100 mumols/l) and benoxaprofen (100 mumols/l) in platelets were qualitatively similar to those of orpanoxin. 4. These results indicate that the discrepancy between the low potency of orpanoxin in inhibiting bovine seminal vesicle cyclo-oxygenase in vitro and its high potency as an anti-inflammatory agent in vivo is not explained by its having an additional lipoxygenase inhibitory mechanism.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Anti-Inflammatory Agents, Non-Steroidal; Arachidonic Acid; Arachidonic Acids; Blood Platelets; Calcimycin; Chromatography, High Pressure Liquid; Female; Humans; In Vitro Techniques; Indicators and Reagents; Indomethacin; Male; Neutrophils; Propionates

Rat alveolar macrophages (AM) collected by bronchoalveolar lavage were incubated in the presence or absence of various icosanoids or inhibitors of the arachidonic acid cascade with either chrysotile asbestos (50 micrograms/ml) to determine cell aggregation, or human red blood cells (Rh+; preincubated with anti-D globulin) to measure phagocytosis. Phorbol myristate acetate (PMA) and ionophore A23187, two agents which stimulate arachidonic acid metabolism, reduced red blood cell phagocytosis by AM whereas arachidonic acid had no effect on this cellular event. Neither arachidonic acid nor its metabolites (prostaglandins E2, I2, F2 alpha, the thromboxane mimick U44069 and leukotrienes A4, B4, C4, D4) had a significant effect on phagocytosis. Inhibition of the synthesis of cyclooxygenase products with various concentrations of indomethacin, aspirin and OKY-1581 or of lipoxygenase products with eicosatetraynoic acid, BW755c, diethylcarbamazine and phenidone did not affect phagocytosis either. On the other hand, asbestos-induced aggregation was significantly reduced by nordihydroguaiaretic acid (NDGA), BW755C, benoxaprofen, and high concentrations of indomethacin but not by aspirin. These results suggested that metabolites of arachidonic acid (especially lipoxygenase products) play a modulatory role in non specific alveolar macrophage aggregation but not in specific, Fc receptor-mediated phagocytosis.

Topics: Animals; Arachidonic Acids; Asbestos; Calcimycin; Cell Aggregation; Cyclooxygenase Inhibitors; Erythrocytes; Humans; Immunoglobulins; Indomethacin; Lipoxygenase Inhibitors; Macrophages; Phagocytosis; Propionates; Pulmonary Alveoli; Rats; Rho(D) Immune Globulin; Tetradecanoylphorbol Acetate

The effect on arachidonate metabolism of two compounds (BW755C and benoxaprofen) which have been reported to inhibit 5' lipoxygenase in leukocytes has been evaluated in human polymorphonuclear leukocytes (PMN) stimulated with the calcium ionophore A23187 and serum-treated zymosan (STZ). The syntheses of leukotriene B4 (LTB4) and thromboxane B2 (TXB2) from endogenous substrate were determined by specific radioimmunoassays as indicators of 5' lipoxygenase and cyclo-oxygenase activity in the PMN respectively. Benoxaprofen inhibited the synthesis of leukotriene B4 by human PMN stimulated with the calcium ionophore A23187, but it was approximately 5 times less potent than BW755C. However, benoxaprofen (IC50 1.6 X 10(-4)M) was approximately 100 times less potent than BW755C (IC50 1.7 X 10(-6)M) at inhibiting leukotriene B4 synthesis induced by serum-treated zymosan. Both drugs inhibited thromboxane synthesis by leukocytes stimulated with A23187 or serum-treated zymosan at similar concentrations (approximately 5 X 10(-6)M). The data obtained using STZ as stimulus are consistent with previous in vivo studies and indicate that benoxaprofen is a relatively selective inhibitor of cyclo-oxygenase. However, this selectivity was far less apparent when A23187 was used as a stimulus to release the eicosanoids which suggests that this inhibition could be via an indirect mechanism and therefore A23187 should be used with caution as a stimulus of 5' lipoxygenase for evaluating inhibitors of eicosanoid synthesis.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Arachidonate Lipoxygenases; Calcimycin; Humans; Leukotriene B4; Lipoxygenase; Neutrophils; Propionates; Pyrazoles; Thromboxane B2; Zymosan

Leukotriene and prostaglandin production by mouse peritoneal macrophages was investigated. It could be shown that the tumour promoter 12-O-tetradecanoylphorbol-13-acetate, despite initiating the release of prostaglandin E2, had little effect on the release of leukotriene C4-like immunoreactivity. The divalent cation ionophore A 23187 at concentrations between 10(-6) and 10(-8) mol/l initiated prostaglandin as well as leukotriene release. This prostaglandin and leukotriene release could be modulated by drugs. Non-steroidal anti-inflammatory drugs inhibited prostaglandin release but enhanced leukotriene production. The experimental compound BW 755C inhibited prostaglandin and leukotriene production, whereas the antithrombotic compound nafazatrom inhibited the production of leukotriene C4-like immunoreactivity but enhanced the prostaglandin E2 production. Nordihydroguaiaretic acid inhibited prostaglandin and leukotriene production. The results show that the metabolism of arachidonic acid in macrophages via the cyclooxygenase or the lipoxygenase pathway is dependent on the stimulus applied. Both pathways can be inhibited conjointly or selectively by drugs. The experimental system described may be used for assessing the potency of drugs to inhibit the lipoxygenase and the cyclooxygenase pathway of arachidonic acid metabolism.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Acetaminophen; Animals; Anti-Inflammatory Agents; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Calcimycin; Dinoprostone; Dipyrone; Indomethacin; Macrophages; Male; Mice; Propionates; Prostaglandins E; Pyrazoles; Pyrazolones; SRS-A

A method for detecting inhibitors of arachidonic acid metabolism is described. Guinea pig peritoneal polymorphonuclear leukocytes incubated with [14C] arachidonic acid were stimulated with calcium ionophore A23187. The radiolabelled products were identified by HPLC and GC/MS as cyclo-oxygenase and lipoxygenase metabolites. A TLC system was utilized to separate these metabolites which were then analysed by automatic quantitative scanning. This method allowed rapid determination of the radiolabel incorporated into each metabolite. This method of analysis was used to study the actions of indomethacin, NDGA, benoxaprofen, and BW775C on the formation of radiolabelled arachidonic acid metabolites.

Topics: 4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyrazol-3-amine; Animals; Anti-Inflammatory Agents; Antioxidants; Arachidonic Acid; Arachidonic Acids; Ascitic Fluid; Biotransformation; Calcimycin; Catechols; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Cyclooxygenase Inhibitors; Gas Chromatography-Mass Spectrometry; Guinea Pigs; Indomethacin; Lipoxygenase Inhibitors; Male; Masoprocol; Neutrophils; Oxygenases; Propionates; Pyrazoles