1,721,041 research outputs found
Effects of selenium and mercury on glutathione and glutathione dependent enzymes in experimental quail
No full textMorphological and biochemical alterations of CHO cultured cells during methyl mercury intoxication and protection with sodium selenite
No full textThe time course of mixed disulfide formation between GSH and proteins in rat blood after oxidative stress with tert-butyl hydroperoxide
No full textVariations in time of GSH, GSSG and glutathione-protein mixed disulfides (GSSP) were studied in rat blood in vitro experiments of oxidative stress with tert-butyl hydroperoxide (t-BOOH, dose range 0.3-2 mM; time range 15 sec-60 min). The aim was to elucidate the potential for GSSG reduction of protein-bound SH groups (PSH). GSSP was estimated by two methods, indirectly from GSHt (GSH + 2 GSSG) variations and directly from precipitated and washed proteins. After treatment with t-BOOH, GSH and GSSG concentrations showed an immediate (15-30 sec) drop and a peak respectively and returned to control levels (time zero values) between 30 and 60 min. A t-BOOH dose-dependent minimum of GSHt and a corresponding GSSP maximum were obtained within 1-6 min and subsequently returned to control values. Basal GSH, GSSG and GSSP levels were similar in aged and fresh blood. In contrast, after treatment with 1 mM t-BOOH substantial differences in kinetic patterns were observed: for intance GSSP concentrations were higher in aged than in fresh blood with no return to the initial values. The pretreatment of aged blood with 10 mM glucose decreased GSSP formation and produced a reversible pattern similar to that observed in fresh blood. The role of glucose in regulating GSSP generation is discussed. © 1994
Disruption of cytoskeleton by methylmercury in cultured CHO cells
No full textThe effect of methylmercury (MM) on three main cytoskeletal components [i.e. microtubules (MT), microfilaments (MF) and intermediate filaments (IF)] and on specific biochemical parameters (i.e. glutathione transferase (GST), glutathione reductase (RED), glutathione peroxidase (GSH-Px), glyoxalase 1 (GLY 1) and total -SH groups (TSH) of the cytosolic fraction) was studied in cultured Chinese hamster ovary (CHO) cells. The experiments were conducted with increasing doses of MM (i.e. 1, 4 and 8 Î1⁄4m), using an exposure time of 16 hr; and with a fixed dose of MM (2 Î1⁄4m), using increasing exposure periods (i.e. 0-24 hr). The morphological changes observed by immunofluorescence seemed to indicate that MF were damaged as much as (if not more than) MT after 16 hr of exposure to 4 Î1⁄4m-MM. At a concentration of 1 Î1⁄4m, MM only affected MF. The time-course experiments revealed that IF as well as MF and MT were severely disorganized after 3 and 6 hr of incubation in the presence of 2 Î1⁄4m-MM. However, an obvious reorganization was observed after 24 hr of exposure. In experiments using increasing MM doses, changes in the enzymatic activities were less noticeable than those observed in the morphology; only a modest decrease in TSH and RED activities (<30%) was recorded at the highest dose of MM used (i.e. 8 Î1⁄4m). In contrast, increasing the time of exposure to MM induced changes in both the cytoskeletal structures and the biochemical parameters: the lowest RED activity and TSH were observed after 3-6 hr exposure; control values were obtained after an exposure period of 24 hr. Ultrastructural observations on cells treated with increasing doses of MM showed changes in plasmamembrane profile, cytoskeleton organization and mitochondrion structure. The results confirm that MM causes non-specific damage to CHO cells and suggest that a functional interaction may exist between GSH-dependent enzymes and cytoskeletal structures. © 1992
Problems in determination of glutathione in rat liver supernatant [PROBLEMI DI DOSAGGIO DEL GLUTATIONE NEL SUPERNATANTE DI FEGATO DI RATTO]
No full textAttività enzimatica di ossidasi a funzione mista (MFO) e di enzimi glutatione dipendenti in popolazioni di gabbiano comune provenienti da aree a diversa contaminazione
No full textLiver glutathione and ligandin in carbon tetrachloride poisoning [GLUTATIONE E LIGANDINA EPATICA NEL DANNO SPERIMENTALE DA TETRACLORURO DI CARBONIO]
No full textDifferent mechanisms of formation of glutathione-protein mixed disulfides of diamide and tert-butyl hydroperoxide in rat blood
No full textThe mechanisms of glutathione-protein mixed disulfide (GSSP) formation caused by diamide and tert-butyl hydroperoxide were studied in rat blood after in vitro treatment in the 0.3–4 mM dose range. tert-Butyl hydroperoxide formed GSSP, via GSSG, according to the reaction, GSSG + PSH → GSSP + GSH, whereas diamide reacted first with protein SH groups, giving PS-diamide adducts and then, after reaction with GSH, GSSP. Moreover, after diamide treatment, GSSP patterns were characterized by a much slower or irreversible dose-related return to basal levels in comparison with those observed with tert-butyl hydroperoxide, always reversible. Experiments with purified hemoglobin revealed the existence of a large fraction of protein SH groups which formed GSSP and had a higher reactivity than GSH. Experiments on glucose consumption and role of various erythrocyte enzymes, carried out to explain the inertness of GSSP to reduction after treatment of blood with diamide, were substantially negative. Other tests carried out to confirm the efficiency of the enzymatic machinery of blood samples successively treated with diamide and tert-butyl hydroperoxide, indicated that GSSP preformed by diamide was difficult to reduce, whereas those generated by tert-butyl hydroperoxide were reversible as normal. Our results suggest that a fraction of GSSP generated by diamide is different and less susceptible to reduction than that obtained with tert-butyl hydroperoxide
Hepatic glutathione content in rats with carbon tetrachloride poisoning [CONTENUTO EPATICO DEL GLUTATIONE IN RATTI INTOSSICATI DA TETRA-CLORURO DI CARBONIO]
No full textMixed-function oxidase activity and conjugating enzymes in two species of Antarctic fish
No full textEnzyme activities of phase I and phase II of the hepatic detoxication system were investigated in two species of fish from the Ross Sea in Antarctica. The fish had extremely low phase I enzyme (BPMO and aldrin epoxidase). The reductase regenerating enzyme activities were comparable to those found in fish of temperate seas. Transferases of cytosol showed highest activity in the
conjugation of l-chloro-2.4-dinitrobenzene (CDNB) and little or no conjugation of other substrates. The GSSG reductase and the glutathione transferase with peroxidase activity (CuOOH substrate) were low; the Sedependent glutathione peroxidase activity was not detectable. Interspecific differences were found for most of the enzymes tested
- …
