α-Tocopheryl succinate (TOS), a redox-silent analogue of vitamin E, suppresses cell growth in a number of clinical and experimental cancers, inhibits mitochondrial succinate dehydrogenase (SDH) and activates reactive oxygen species (ROS) generation. The aim of this study was to test whether TOS also inhibits glycerol-3-phosphate dehydrogenase (mGPDH), another flavoprotein-dependent enzyme of the mitochondrial respiratory chain because there are differences between electron transfer pathway from SDH and mGPDH to coenzyme Q pool. For our experiments brown adipose tissue mitochondria with high expression of mGPDH were used. Our data showed that inhibition of glycerol-3-phosphate (GP)-dependent oxygen consumption by TOS was more pronounced than the succinate (SUC)-dependent one (50% inhibition was reached at 10 μmol/l TOS vs. 80 μmol/l TOS, respectively). A comparison of the inhibitory effect of TOS on GP-oxidase, GP-cytochrome c oxidoreductase and GP-dehydrogenase activities showed that TOS directly interacts with the dehydrogenase. After TOS application the GP-dependent generation of ROS was highly depressed. It may thus be concluded that TOS-induced inhibition of mGPDH is more pronounced than TOS-induced inhibition of SDH and that the inhibitory effect of TOS for both substrates is exerted at different locations of the particular dehydrogenases. Our data indicate that the inhibition of mGPDH activity could also play a role in TOS-induced growth suppression in neoplastic cells.
- MeSH
- alfa-tokoferol aplikace a dávkování MeSH
- glycerolfosfátdehydrogenasa antagonisté a inhibitory biosyntéza MeSH
- hnědá tuková tkáň enzymologie MeSH
- karcinogeneze genetika MeSH
- křečci praví MeSH
- lidé MeSH
- mitochondrie účinky léků enzymologie MeSH
- nádory farmakoterapie enzymologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- regulace genové exprese u nádorů účinky léků MeSH
- spotřeba kyslíku účinky léků MeSH
- zvířata MeSH
- Check Tag
- křečci praví MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Adipose tissue is an important target for thyroid hormones (TH). However, the metabolism of TH in white adipose tissue is poorly characterized. Our objective was to describe possible changes in activities of TH-metabolizing enzymes in white adipose tissue, and the role of TH metabolism in the tissue during obesogenic treatment, caloric restriction and in response to leptin in mice. Activity of type I iodothyronine 5’-deiodinase (D1) in white fat was stimulated by a high-fat diet, which also increased plasma leptin levels, while brown adipose tissue D1 activity did not change. Caloric restriction decreased the activity of D1 in white fat (but not in the liver), reduced leptin levels, and increased the expression of stearoyl CoA desaturase 1 (SCD-1), a marker and mediator of the effect of leptin on tissue metabolism. Leptin injections increased D1 activity and down-regulated SCD-1 in white fat. Our results demonstrate changes in D1 activity in white adipose tissue under the conditions of changing adiposity, and a stimulatory effect of leptin on D1 activity in the tissue. These results suggest a functional role for D1 in white adipose tissue, with D1 possibly being involved in the control of adipose tissue metabolism and/or accumulation of the tissue.
- MeSH
- bílá tuková tkáň enzymologie patofyziologie MeSH
- financování organizované MeSH
- fyziologie výživy zvířat MeSH
- hnědá tuková tkáň enzymologie patofyziologie MeSH
- hormony štítné žlázy metabolismus MeSH
- injekce subkutánní MeSH
- jodidperoxidasa genetika metabolismus MeSH
- kalorická restrikce MeSH
- leptin aplikace a dávkování genetika metabolismus MeSH
- messenger RNA metabolismus MeSH
- modely nemocí na zvířatech MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- obezita enzymologie patofyziologie MeSH
- regulace genové exprese enzymů MeSH
- rekombinantní proteiny metabolismus MeSH
- stearyl-CoA-desaturasa genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
Idebenone (IDE), a synthetic analog of coenzyme Q, strongly activates glycerol phosphate (GP) oxidation in brown adipose tissue mitochondria. GP oxidase, GP cytochrome c oxidoreductase and GP dehydrogenase activities were all significantly stimulated by 13 muM IDE. Substituted derivatives of IDE acetyl- and methoxyidebenone had similar activating effects. When succinate was used as substrate, no activation by IDE could be observed. The activation effect of IDE could be explained as release of the inhibition of glycerol phosphate dehydrogenase by endogenous free fatty acids. NADH oxidoreductase activity and oxidation of NADH-dependent substrates were inhibited by IDE. The extent of the inhibition and IDE concentration dependence varied when various substrates were tested, being highest for pyruvate and lowest for 2-oxoglutarate. This study thus showed that the effect of IDE on various mitochondrial enzymes is very different and thus its therapeutic use should take into account its specific effect on various mitochondrial dehydrogenases in relation to particular defects of mitochondrial respiratory chain.
- MeSH
- aktivace enzymů účinky léků MeSH
- financování organizované MeSH
- hnědá tuková tkáň enzymologie účinky léků MeSH
- křečci praví MeSH
- kultivované buňky MeSH
- mitochondrie metabolismus účinky léků MeSH
- transport elektronů fyziologie MeSH
- ubichinon analogy a deriváty aplikace a dávkování MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- křečci praví MeSH
- mužské pohlaví MeSH
- zvířata MeSH
Involvement of mammalian mitochondrial glycerophosphate dehydrogenase (mGPDH, EC 1.1.99.5) in reactive oxygen species (ROS) generation was studied in brown adipose tissue mitochondria by different spectroscopic techniques. Spectrofluorometry using ROS-sensitive probes CM-H2DCFDA and Amplex Red was used to determine the glycerophosphate- or succinate-dependent ROS production in mitochondria supplemented with respiratory chain inhibitors antimycin A and myxothiazol. In case of glycerophosphate oxidation, most of the ROS originated directly from mGPDH and coenzyme Q while complex III was a typical site of ROS production in succinate oxidation. Glycerophosphate-dependent ROS production monitored by KCN-insensitive oxygen consumption was highly activated by one-electron acceptor ferricyanide, whereas succinate-dependent ROS production was unaffected. In addition, superoxide anion radical was detected as a mGPDH-related primary ROS species by fluorescent probe dihydroethidium, as well as by electron paramagnetic resonance (EPR) spectroscopy with DMPO spin trap. Altogether, the data obtained demonstrate pronounced differences in the mechanism of ROS production originating from oxidation of glycerophosphate and succinate indicating that electron transfer from mGPDH to coenzyme Q is highly prone to electron leak and superoxide generation.
- MeSH
- antimycin A analogy a deriváty farmakologie MeSH
- buněčné dýchání MeSH
- elektronová paramagnetická rezonance MeSH
- ethidium analogy a deriváty chemie MeSH
- ferrikyanidy farmakologie MeSH
- financování organizované MeSH
- glycerolfosfátdehydrogenasa metabolismus MeSH
- glycerolfosfáty metabolismus MeSH
- hnědá tuková tkáň enzymologie účinky léků ultrastruktura MeSH
- křečci praví MeSH
- mitochondrie enzymologie metabolismus účinky léků MeSH
- reaktivní formy kyslíku analýza metabolismus MeSH
- respirační komplex III metabolismus MeSH
- spotřeba kyslíku MeSH
- transport elektronů MeSH
- ubichinon metabolismus MeSH
- zvířata MeSH
- Check Tag
- křečci praví MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- MeSH
- finanční podpora výzkumu jako téma MeSH
- hnědá tuková tkáň enzymologie fyziologie metabolismus MeSH
- hormony štítné žlázy fyziologie metabolismus MeSH
- lidé MeSH
- proteiny fyziologie metabolismus MeSH
- rozpřahující látky metabolismus MeSH
- steroidy fyziologie metabolismus MeSH
- svaly enzymologie metabolismus MeSH
- termogeneze fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
- MeSH
- glukokortikoidy fyziologie MeSH
- hlad fyziologie MeSH
- hladovění enzymologie komplikace MeSH
- hnědá tuková tkáň enzymologie MeSH
- hypothalamus enzymologie MeSH
- krysa rodu rattus MeSH
- oxidoreduktasy analýza fyziologie MeSH
- volné radikály metabolismus škodlivé účinky MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- MeSH
- glycerolfosfátdehydrogenasa metabolismus MeSH
- hnědá tuková tkáň enzymologie metabolismus MeSH
- křečci praví MeSH
- mitochondrie enzymologie MeSH
- oxidace-redukce MeSH
- transport elektronů MeSH
- ubichinon analogy a deriváty analýza metabolismus MeSH
- zvířata MeSH
- Check Tag
- křečci praví MeSH
- zvířata MeSH
- MeSH
- hnědá tuková tkáň enzymologie MeSH
- lipoproteinlipasa metabolismus MeSH
- membránové proteiny genetika imunologie metabolismus MeSH
- myši MeSH
- obezita genetika patofyziologie patologie MeSH
- respirační komplex IV imunologie metabolismus MeSH
- transportní proteiny genetika MeSH
- tuková tkáň enzymologie patologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
