Biomaterial Database

Hydrocortisone inhibits the respiratory burst oxidase from human neutrophils in whole-cell and cell-free systems. 1990

S Umeki, and R Soejima

Department of Medicine, Kawasaki Medical School, Okayama, Japan.

The effects of hydrocortisone on the respiratory burst oxidase (NADPH oxidase, EC 1.6.99.6) from human neutrophils in both whole-cell and full soluble (cell-free) systems were investigated. In the whole-cell system, hydrocortisone inhibited the generation of superoxide by neutrophils exposed to phorbol myristate acetate, suggesting that steroids inhibit the bactericidal capacity of the body in an acute inflammatory phase. Hydrocortisone, which was added to the cuvette after the addition of NADPH and before the addition of sodium dodecyl sulfate, in a cell-free system, was found to inhibit the activation of superoxide-generating NADPH oxidase by sodium dodecyl sulfate. The concentration of hydrocortisone required for 50% inhibition of oxidase was 40 microM. Its inhibition was dose- and time-dependent in the cell-free system. However, hydrocortisone did not alter the Km of the oxidase for NADPH. These results suggest that steroids inhibit the reconstitution of NADPH oxidase by sodium dodecyl sulfate in the cell-free system, and that they do not alter the affinity to NADPH of the oxidase.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D009247	NADH, NADPH Oxidoreductases	A group of oxidoreductases that act on NADH or NADPH. In general, enzymes using NADH or NADPH to reduce a substrate are classified according to the reverse reaction, in which NAD+ or NADP+ is formally regarded as an acceptor. This subclass includes only those enzymes in which some other redox carrier is the acceptor. (Enzyme Nomenclature, 1992, p100) EC 1.6.	Oxidoreductases, NADH, NADPH,NADPH Oxidoreductases NADH,Oxidoreductases NADH, NADPH
D009249	NADP	Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)	Coenzyme II,Nicotinamide-Adenine Dinucleotide Phosphate,Triphosphopyridine Nucleotide,NADPH,Dinucleotide Phosphate, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide Phosphate,Nucleotide, Triphosphopyridine,Phosphate, Nicotinamide-Adenine Dinucleotide
D009504	Neutrophils	Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.	LE Cells,Leukocytes, Polymorphonuclear,Polymorphonuclear Leukocytes,Polymorphonuclear Neutrophils,Neutrophil Band Cells,Band Cell, Neutrophil,Cell, LE,LE Cell,Leukocyte, Polymorphonuclear,Neutrophil,Neutrophil Band Cell,Neutrophil, Polymorphonuclear,Polymorphonuclear Leukocyte,Polymorphonuclear Neutrophil
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D002474	Cell-Free System	A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)	Cellfree System,Cell Free System,Cell-Free Systems,Cellfree Systems,System, Cell-Free,System, Cellfree,Systems, Cell-Free,Systems, Cellfree
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006854	Hydrocortisone	The main glucocorticoid secreted by the ADRENAL CORTEX. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions.	Cortef,Cortisol,Pregn-4-ene-3,20-dione, 11,17,21-trihydroxy-, (11beta)-,11-Epicortisol,Cortifair,Cortril,Epicortisol,Hydrocortisone, (11 alpha)-Isomer,Hydrocortisone, (9 beta,10 alpha,11 alpha)-Isomer,11 Epicortisol
D013481	Superoxides	Highly reactive compounds produced when oxygen is reduced by a single electron. In biological systems, they may be generated during the normal catalytic function of a number of enzymes and during the oxidation of hemoglobin to METHEMOGLOBIN. In living organisms, SUPEROXIDE DISMUTASE protects the cell from the deleterious effects of superoxides.	Superoxide Radical,Superoxide,Superoxide Anion
D019255	NADPH Oxidases	A family of membrane-associated flavoprotein NADPH-dependent oxidoreductases that catalyze the univalent reduction of OXYGEN to create SUPEROXIDES. Structurally, they are characterized by six N-terminal transmembrane ALPHA-HELICES, a FLAVIN-ADENINE DINUCLEOTIDE (FAD)-binding region, and a C-terminal NADPH-binding region. They are expressed primarily by EPITHELIAL CELLS in gut, kidney, colon, and smooth muscle tissues, as well as GRANULOCYTES and function to transfer electrons across membranes to molecular oxygen. Defects in the production of superoxide ions by some NADPH oxidases result in GRANULOMATOUS DISEASE, CHRONIC.	NADPH Oxidase,NAD(P)H Oxidases,NAD(P)H oxidase,Nox Proteins,Oxidase, NADPH,Oxidases, NADPH