L. Szabó

A comparative study of some more important experimental animal peroxide metabolism enzymes

1. We have studied and compared the peroxide metabolism enzymes (SOD, P and C) of the main organs of fresh-water mollusc, chicken, mouse, guinea-pig, rabbit, cat and dog. 2. The liver exhibited the highest SOD activity. The enzymatic activities of the organ homogenates of the guinea-pig stand out in comparison with the values for the other homogenates examined. 3. The liver, kidney and total brain homogenates of the chicken and the vertebrates display no, or only a very low P activity. The highest P activities were measured in the haemolysates. 4. The C and SOD values exhibit a certain parallelism. 5. The peroxide metabolism enzyme activities calculated by utilizing the protein measurements permit the establishment of a more realistic enzymatic activity.

In vivo study of the mechanism of protective effects of ascorbic acid and reduced glutathione in paraquat poisoning

Abstract 1. 1. On the basis of our earlier experiments, in vivo studies were carried out to decide how the optimum concentrations of ascorbic acid and reduced glutathione, administered parenterally at two different times, influence the paraquat LD 50 toxicity. 2. 2. Another aim was the molecular biochemical study of their protective effects. 3. 3. It was found that both substances influence the in vivo action of paraquat, but they are not able fully to prevent or eliminate them. 4. 4. The positive detoxicating effect of ascorbic acid may be emphasized.

Paraquat as an agent affecting antioxidant enzymes of common carp erythrocytes

The effects of paraquat on the superoxide dismutase, catalase, glutathionine peroxidase activities and lipid peroxidation at different times of paraquat exposure of Cyprinus carpio morph L. erythrocytes were studied. Typical characteristics were observed in the changes of the enzyme activities of the erythrocytes after exposure to paraquat. The haemoglobin concentration of common carp haemolysates was decreased by exposure to paraquat.

Effects of neuroleptics on the lipid peroxidation and peroxide metabolism enzyme activities in various discrete areas of the rat brain

The effects of a 7-day treatment with Haloperidol or reserpine (in both cases 0.1 mg/kg per day) were studied on the superoxide dismutase and catalase activities and the lipid peroxidation in various discrete regions of the rat brain. It was found that these neuroleptics change the lipid peroxidation and the activities of the enzymes in similar directions in the brain areas tested.

Effects of paraquat on peroxide metabolism enzymes and lipid peroxidation in the rat

Investigation has been made of how the LD50 and LD100 of PQ influence the peroxide metabolism enzymes and lipid peroxidation in organ homogenates and blood samples of the rat. The peroxide metabolism enzyme activities were changed in a concentration dependent manner. In general, the effect of the lower doses of PQ on the superoxide dismutase, catalase activities and lipid peroxidation are increased. The glutathione peroxidase activity was decreased. Higher doses of PQ enhanced all of enzyme activities and lipid peroxidation studied.

Some further data on the effects of two organophosphate pesticides on the oxidative metabolism in the liver

Sumithion is the most active cholinesterase inhibitor. The cholinesterase inhibiting action of the organophosphates (OPs) is better compensated by vitamin E in normal animals, but by vitamin A in vitamin A-deficient animals. The lipid peroxidation (LP) is enhanced by the antioxidant vitamins in the liver of normal rats; although they decrease it in the liver of vitamin A-deficient animals, in no case do they prevent the LP-enhancing effect of the OPs examined. The OPs examined inhibit protein synthesis in the liver of vitamin A-deficient animals.

In vivo effects of paraquat on some oxidative enzymes of mice

Abstract 1. By means of a comparison with untreated controls, a study was made of the effects of LD50 and LD100 of paraquat in vivo on the peroxide metabolism enzymes (superoxide dismutase, peroxidase and catalase), on the tissue lipid peroxidation, and on the microsomal cytochrome P-450 concentrations of the main organs. 2. The results reveal that the enzymes and the tissue properties compared are influenced by the herbicide in different manners, depending on its concentration. 3. The effect is connected first of all with the redox properties of paraquat, which in mice acts either as an electron donor or as an electron acceptor, depending on its concentration.

Some new data to the toxicological effects of paraquat and the therapy

1. Substances previously tested therapeutically were studied to obtain evidence on the pathomechanism in mice of paraquat, the active ingredient of Gramoxon, connected with the radicals formed from molecular oxygen, and also to extend the therapeutic possibilities. 2. The effects of these substances were assessed on the basis of the 72-hr survival rate and the percentage ratio of the wet lung weight to the overall body weight. 3. Other toxicological parameters too were followed. 4. Our present investigations indicate that, in agreement with our earlier results, besides reduced glutathione and ascorbic acid, vitamin E and C-ase are of the greatest importance from the aspect of the protection against paraquat toxicity. 5. In addition to those listed, other materials too, e.g. antifibrotic substances, naturally possess considerable detoxicating properties too.

The effects of organophosphate pesticides on some liver enzymes and lipid peroxidation

Abstract 1. 1. The effects of two organophosphate pesticides, Triklorfon and Sumithion were studied. One of them is inactive in vitro and is activated metabolically; the other is a thionophosphate which is oxidized in the liver to the corresponding oxone. 2. 2. The following liver enzymes and components were determined and compared in addition to the liver lipid peroxidation (LP): 1. Cholinesterase (ChE; EC 3.1.1.8). 2. Superoxide dismutase (SOD; EC 1.15.1.1) and catalase (C-ase; EC 1.11.1.6). 3. Microsomal (liver) cytochrome P-450 activity. 4. Protein and in some cases the activity of (Mg2+ + Na+ + K+)-adenosine-triphosphatase (ATP-ase; EC 3.6.1.3). 3. 3. On the basis of our earlier observations, an effort was made to clarify the molecular mechanism of action of the two organophosphate pesticides.

Effects of paraquat in vivo on fatty acids of mouse and guinea pig tissues

Abstract 1. 1. The influence of the LD50 and LD100 of paraquat on the fatty acid compositions of the large organs was studied in vivo in experimental animals/mouse and guinea pig. 2. 2. Paraquat exerts a considerable concentration-dependent effect on the fatty acid compositions of the organs, and also probably acts on the enzymes of fatty acid transformation.