Forms Of Pyridine Nucleotides Research Articles

Efficiency of ademethionine in oxidative stress in tissues of irradiated rats

Introduction. Ionizing radiation in low doses of low intensity causes prolonged activation of lipid per oxidation and depletion of the antioxidant system in a living organism. Moreover, Ademethionine is currently being considered as a promising antioxidant.Method. Experimental studies were carried out on 60 sexually mature male Wistar rats. The animals were irradiated in a total dose of 1Gy on a γ-therapeutic device AGAT-R No. 83 (isotope 60Co). At the end of the total dose, the rats were injected intraperitoneally with Heptral (ademethionine) after 15 minutes, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156 hours after radiation exposure at the rate of 10 mg / kg mass. After the introduction of Heptral, the animals were taken into the experiment after 24 hours, 3, 7, 15 days. In homogenates of the spleen and thymus of animals, the amount of oxidized and reduced forms of pyridine nucleotides was determined.Results. Chronic γ-irradiation in a total dose of 1Gy leads to a significant decrease in the content of reduced forms of pyridine nucleotides in the spleen and thymus of rats. Administration of Heptral to irradiated animals normalized oxidative homeostasis. So, on the 7th day of the experiment, the amount of oxidized forms of pyridine nucleotides in the spleen was 47.3% lower, and reduced - 36.3% higher than in animals that did not receive treatment. At the end of the observation period, the reduction coefficient of pyridine nucleotides in the spleen slightly differed from the control level. In comparison with irradiated animals, which were not injected with Heptral, the NADP content was lower by 70.3%, and NADPH2 - higher by 48.8%.Conclusion. The course administration of Heptral to irradiated animals leads to the normalization of the reduction factor of pyridine nucleotides. According to its mechanism of action, Heptral can be used in the complex treatment of low- intensity radiation injuries in low doses.

Changes in pyridine nucleotide levels in leaves and roots of bean plants ( Phaseolus vulgaris L.) during phosphate deficiency

Summary A large decrease in inorganic phosphate content in bean plants ( Phaseolus vulgaris L. cv. Zlota Saxa) grown on phosphate deficient medium induced the changes in the levels of pyridine nucleotides. The decrease in the level of NADP + was noted only in roots. However, NAD + content decreased both in leaves and roots. In −P leaves and roots the concentration of NADPH increased, but the content of NADH did not change. More pronounced changes in the levels of pyridine nucleotides in roots as compared with leaves might be a result of the effect of Pi-deficiency on the overall rate of respiration. Modifications in the respective nucleotide levels were reflected by higher values of the NADPH/NADP + , NADH/NAD + and RC ratios both in leaves and roots. Relative accumulation of reduced forms of pyridine nucleotides in 18-day-old −P bean plants indicates that the equilibrium of oxidation-reduction reactions was shifted in the direction of redox equivalents-yielding system both in leaves and roots. Cytosolic NAD + -dependent malate dehydrogenase and NADP + -malic enzyme activities showed changes dependent on the level of particular forms of pyridine nucleotides. The changes in the levels of particular forms of pyridine nucleotides after 14 days of plant growth without Pi in the nutrient medium appear to be a delayed plant response to phosphate deficit stress.

Effect of methylxanthines (theophylline, theobromine, caffeine) and catecholamines on nicotinamide coenzyme content in the rat myocardium

In experiments on rats, after intraperitoneal injection of theophylline the content of oxidized forms of pyridine nucleotides (NAD+NADP) was reduced by 19.4%, the level of the reduced forms (NAD·H2+NADP·H2) showed a tendency to decrease, and the total content of nicotinamide coenzymes was significantly reduced. After administration of caffeine the content of NAD+NADP and the total pyridine nucleotides showed a tendency to decrease. Theobromine had no significant effect on these parameters. The action of catecholamines and methylxanthines was compared. Isoproternol (exciting β-adrenergic receptors) lowered the NAD+NADP content, but adrenalin (25 μg/kg) increased the content of both oxidized (by 24%) and reduced (48%) forms of pyridine nucleotides. An increase in the dose of adrenalin (1000 μg/kg) led to a decrease in the level of oxidized forms (by 22.2%) and of the total nicotinamide coenzymes (by 18%).

Effects of illumination and oxygen supply upon the levels of pyridine nucleotides in Chlorella cells

1.1. Using intact cells of Chlorella, investigations were made on the effect of light on the levels of various forms of pyridine nucleotides, compared with that on the photogenic reducing agent (R).2.2. No form of pyridine nucleotide was found of which the concentration was affected in the same manner as that of R, which has been known to be produced only in the light and eliminated completely in the dark.3.3. Under both aerobic and anaerobic conditions, light decreased the level of DPN+ and increased the level of TPN. Quantitatively, there was a correspondence between these effects.4.4. When algal cells were transferred in the dark from anaerobic to aerobic conditions, a marked decrease of DPNH occurred, the levels of DPN+, TPN+ and TPNH remaining almost unchanged. The decrease of DPNH in the light (in N2) was assumed to be brought about by the O2 produced concomitantly with the photogenic formation of R and effecting the transfer of DPNH to some substance other than DPN+.5.5. It was concluded that (a) neither TPNH nor DPNH is the primary R and that (b) one of the effects caused by light is the conversion of DPN+ to TPN.