An inhibitor of diacylglycerol kinase, R59022, enhanced activation of the neutrophil oxidase stimulated by the Ca2+-ionophore, A23187 (1 microM), and by N-formyl-methionyl leucyl-phenylalanine (1 microM). The enhancement was reversed by two inhibitors of c-kinase, retinal (10 microM), and gossypol (20 microM). Activation by phorbol-myristyl-acetate and unopsonised latex beads were not enhanced. It was concluded that the chemotactic peptide generated diacylglycerol, but that maximum activation of c-kinase by this route was not achievable. The role of diacylglycerol in activation by beads remained unclear.

Conference Article| October 01 1986 Retinoids interact with the mechanism of neutrophil oxidase activation ERYL COOKE; ERYL COOKE 1University Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff CF4 4XN, U.K. Search for other works by this author on: This Site PubMed Google Scholar MAURICE B. HALLETT MAURICE B. HALLETT 1University Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff CF4 4XN, U.K. Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1986) 14 (5): 954–955. https://doi.org/10.1042/bst0140954 Article history Received: April 04 1986 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation ERYL COOKE, MAURICE B. HALLETT; Retinoids interact with the mechanism of neutrophil oxidase activation. Biochem Soc Trans 1 October 1986; 14 (5): 954–955. doi: https://doi.org/10.1042/bst0140954 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search Keywords: PMA, phorbol myristate acetate, fMet-Leu-Phe, formyl-methionyl-leucyl-phenylalanine This content is only available as a PDF. © 1986 Biochemical Society1986 Article PDF first page preview Close Modal You do not currently have access to this content.

Recent studies have demonstrated tamoxifen inhibition of the enzyme protein kinase C (PKC) in vitro. The aim of this study was to investigate the effects of tamoxifen on PKC function in intact human cells. As PKC activates the neurotrophil oxidase mechanism the neutrophil was chosen as an experimental model to assess PKC-tamoxifen interaction in these experiments. Neutrophils from healthy volunteers were separated by centrifugation through Ficoll Hypaque. Two separate parameters of oxidase activation; oxygen consumption and reactive oxygen metabolite production were monitored by a Clark electrode chamber and luminol dependent chemiluminescence respectively. Neutrophil chemiluminescence was markedly stimulated by 4 Phorbol-12 myristate-13 acetate (PMA). This stimulation was inhibited by tamoxifen; ic50 = 6.1 ± 1.6 μM (x ± S.E.M.) N = 6. Neutrophil oxygen consumption was similarly stimulated by PMA and inhibited by tamoxifen. The tamoxifen inhibition was not due to cell toxicity as assessment of cell integrity by the exclusion of trypan blue and measurement of intracellular concentrations of ATP showed no significant differences before and after treatment. Tamoxifen also inhibited neutrophil chemiluminescence which was stimulated by oleoyl acetyl glycerol and mezerein excluding interaction with PMA as an explanation of its inhibitory effect. These results are consistent with tamoxifen inhibition of PKC function in intact human cells. This may be central to its antitumour action.

The role of C-kinase in the triggering of the neutrophil oxidase by two stimuli (latex beads and the chemotactic peptide fMet-Leu-Phe), representative of endocytotic and exocytotic routes of activation, were investigated by using experimental agents that activate, or inhibit C-kinase, in intact cells. The activation by the phagocytotic stimulus latex beads was mimicked by C-kinase activators giving the same characteristic lag (20-30s), followed by a constant oxygen consumption rate with the same maximum rate and affinity for oxygen (Km approx. 13 microM), competed with activation by PMA (4 beta-phorbol 12-myristate 13-acetate) in a simple common-target manner, and was inhibited by retinal, an inhibitor shown to inhibit activation by PMA. In contrast, activation by chemotactic peptide was not mimicked by C-kinase activation alone, chemotactic peptide inducing biphasic oxygen consumption with a Km for oxygen of the second prolonged phase of 3.9 microM, did not compete with activation by PMA, and was not inhibited by retinal. However, PMA and retinal produced slight enhancements of activation by chemotactic peptide and production of monophasic oxygen consumption. It was concluded that C-kinase activation plays a simple central transducing role in activation of the oxidase by latex beads, but that its role in activation by chemotactic peptide is a part of a more complex set of interactions that involve other Ca2+-activated and non-Ca2+-activated processes.

Conference Article| December 01 1985 The role of microfilaments in polymorphonuclear leucocyte oxidase activation E. COOKE; E. COOKE *Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff CF4 4XN, U.K. Search for other works by this author on: This Site PubMed Google Scholar F. AL-MOHANNA; F. AL-MOHANNA †Department of Biochemistry, University College Cardiff, Park Place, Cardiff CF1 1XL., U.K. Search for other works by this author on: This Site PubMed Google Scholar M. B. HALLETT M. B. HALLETT *Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff CF4 4XN, U.K. Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1985) 13 (6): 1173–1174. https://doi.org/10.1042/bst0131173 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation E. COOKE, F. AL-MOHANNA, M. B. HALLETT; The role of microfilaments in polymorphonuclear leucocyte oxidase activation. Biochem Soc Trans 1 December 1985; 13 (6): 1173–1174. doi: https://doi.org/10.1042/bst0131173 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search Keywords: CB, cytochalasin B, fMLP, formyl-methionyl-leucyl-phenylalanine, PMA, phorbol 12-myristate 13-acetate, PMN, polymorphonuclear leucocyte This content is only available as a PDF. © 1985 Biochemical Society1985 Article PDF first page preview Close Modal You do not currently have access to this content.