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4 Acta Biochimica Polonica

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Coupling of glutathione system and synaptosmal membrane state under L-methionine treatment against oxidative stress

100%

Slyshenkov V. S. , Shevalye A. A. , Moiseenok A. G.

tom 53

nr Supplement 1

Protective effect of pantothenic acid and related compounds against permeabilization of Ehrlich ascites tumour cells by digitonin

100%

Slyshenkov V. S. , Rakowska M. , Wojtczak L.

tom 43

nr 2

Preincubation of Ehrlich ascites tumour cells with millimolar concentrations of pantothenic acid, pantothenol or pantethine, but not with homopantothenic acid, at 22°C or 32°C, but not at 0°C, makes the plasma membrane more resistant to the damaging effect of submillimoiar concentrations of digitonin. It is proposed that this increased resistance is due to the increased rate of cholesterol biosynthesis. In fact, incorporation of [14C]acetate into cholesterol is by 45% increased in the cells preincubated with pantothenic acid; this probably reflects elevation of the content of CoA in such cells [Slyshenkov, V.S., Rakowska, M., Moiseenok, A.G. & Wojtczak, L. (1995) Free Radical Biol. Med. 19,767-772].

Protective role of L-methionine against free radical damage of rat brain synaptosomes

100%

Slyshenkov V. S. , Shevalye A. A. , Liopo A. V. , Wojtczak L.

Acta Biochimica Polonica

2002

tom 49

nr 4

Incubation of rat brain synaptosomal/mitochondrial fraction with ieri-butyl- hydroperoxide resulted in accumulation of the lipid peroxidation product, conjugated dienes, damage of the synaptosomal membrane as evidenced by leakage of lactate dehydrogenase, and decrease of the total content of glutathione and of the GSH/GSSG ratio. This treatment also produced a considerable decrease of the ouabain-sensitive ATPase activity and a much smaller diminution of the activities of glutathione reductase and glutathione transferase. Preincubation of the synaptosomal/mitochon- drial fraction with 0.5 or 1.0 mM L-methionine significantly protected against lipid peroxidation, membrane damage and changes in the glutathione system produced by low (1 mM) concentrations of ieri-butylhydroperoxide and completely prevented inac- tivation of ouabain-sensitive ATPase, glutathione reductase and glutathione transferase by such treatment. The importance of L-methionine in antioxidant protection is discussed.

Protection by pantothenol and beta-carotene against liver damage produced by low-dose gamma-radiation

88%

Slyshenkov V. S. , Omelyanchik S. N. , Moiseenok A. G. , Petushok N. E. , Wojtczak L.

tom 46

nr 2

Rats were exposed to a total dose of 0.75 Gy of γ radiation from a 60Co source, receiving three doses of 0.25 Gy at weekly intervals. During two days before each irradiation, the animals received daily intragastric doses of 26 mg pantothenol or 15 mg β-carotene per kg body mass. The animals were killed after the third irradiation session, and their blood and livers were analyzed. As found previously (Slyshenkov, V.S., Omelyanchik, S.N., Moiseenok, A.G., Trebukhina, R.V. & Wojtczak, L. (1998) Free Radical Biol. Med. 24, 894-899), in livers of animals not supplied with either pantothenol or β-carotene and killed one hour after the irradiation, a large accumulation of lipid peroxidation products, as conjugated dienes, ketotrienes and thiobarbituric acid-reactive substances, could be observed. The contents of CoA, pantothenic acid, total phospholipids, total glutathione and GSH/GSSG ratio were considerably decreased, whereas the NAD/NADH ratio was increased. All these effects were alleviated in animals supplied with β-carotene and were completely abolished in animals supplied with pantothenol. In the present paper, we extended our observations of irradiation effects over a period of up to 7 days after the last irradiation session. We found that most of these changes, with the exception of GSH/GSSG ratio, disappeared spontaneously, whereas supplementation with β-carotene shortened the time required for the normalization of biochemical parameters. In addition, we found that the activities of glutathione reductase, glutathione peroxidase, catalase and NADP-dependent malate (decarboxylating) dehydrogenase ('malic enzyme') in liver were also significantly decreased one hour after irradiation but returned to the normal level within 7 days. Little or no decrease in these activities, already 1 h after the irradiation, could be seen in animals supplemented with either β-carotene or pantothenol. It is concluded that pantothenol is an excellent radioprotective agent against low-dose γ radiation.