Effects of ovarian steroids on superoxide dismutase activity in the rat brain

The levels of manganese superoxide dismutase (MnSOD) and copper-zinc superoxide dismutase (CuZnSOD) were determined in appropriate subcellular fractions prepared from whole brain homogenates of cycling and long-term (3 week) ovariectomized (OVX) Wistar rats, and were compared to the levels found in corresponding samples prepared from OVX rats treated with progesterone (P) or estradiol 17B-benzoate (EB). The activity of both SODs was steady during the estrous cycle, except at proestrus, when MnSOD activity was elevated significantly. Bilateral ovariectomy resulted three weeks later in an increase of the MnSOD activity even higher than that recorded at proestrus. High post-castration MnSOD activity was lowered profoundly by exogenous P (2 mg) or EB (0.5 g), given s.c. to OVX animals 2 h or 24 h before sacrifice. Neither removal of the ovaries nor the hormone treatments affected the activity of CuZnSOD. These results suggest suppressive effects of ovarian steroids on MnSOD activity in the rat brain.     

Effects of progesterone and estradiol benzoate on superoxide dismutase activity in the brain of male rats

The activities of mitochondrial, manganese-containing superoxide dismutase (MnSOD) and cytoplasmic, copper-zinc-containing superoxide dismutase (CuZnSOD) were measured in subcellular fractions of whole brain homogenates prepared from intact and gonadectomized (GDX) male rats, untreated or treated subcutaneously (sc) with a single dose of 2 mg progesterone (P) and/or 5 g estradiol benzoate (EB). Neither MnSOD nor CuZnSOD was affected by the removal of the testes. Similarly, CuZnSOD activity was steady following systemic administration of P and/or EB to intact and GDX animals 2 h or 24 h prior to sacrifice. On the other hand, both P and EB suppressed MnSOD in the brain of either intact or GDX rats. These results suggest involvement of P and EB in the control of MnSOD activity in the brain of male rats.     

Chromosome aberrations,micronuclei, and activity of superoxide dismutases in human lymphocytes after irradiation in vitro

The goal of this study was to provide data on the dose-dependent production of dicentrics and micronuclei in human lymphocytes irradiated with 22.6 MeV protons and to estimate the possible contribution of intracellular superoxide dismutases (SOD) to the relative biological effectiveness (RBE) of protons. For the dose-response study, heparinized whole blood of a healthy volunteer was irradiated with protons and X-rays employing radiation doses of 0.5-4 Gy. Three biological endpoints were analyzed: chromosomal aberrations, micronuclei, and specific activity of cytosolic (CuZnSOD) and mitochondrial (MnSOD) superoxide dismutases in harvested human blood cells. Dicentric dose-response curves fit a linear-quadratic form (alpha = 0.094 +/- 0.006, beta = 0.032 +/- 0.001) induced with X-rays and (alpha = 0.119 +/- 0.057, beta = 0.029 +/- 0.014) for 22.6 MeV protons. Protons were more effective than X-rays in producing exchanges, particularly at 0.5 and 1 Gy. In contrast to X-ray irradiated samples where a significant increase in the specific activity of MnSOD was recorded (up to a radiation dose of 1 Gy), irradiation with protons markedly reduced its activity. As a consequence of the reduced activity of MnSOD, the chromosomal dose-response curve became quadratic. The RBE for dicentrics varies with dose (from 2.2 to 1.01) and reduced activity of MnSOD is an important contributor to the RBE of protons. SODs, particularly MnSOD, play an important role in defending DNA from reactive oxygen species. A reduced activity of SOD, particularly MnSOD, is an important contributor to the RBE of protons.     

Superoxide dismutase activity in the Spanish population

Superoxide dismutase is an enzyme that catalyzes the dismutation of superoxide radicals to hydrogen peroxide and molecular oxygen. This superoxide radical is produced by all aerobic cells as a normal metabolic intermediate of molecular oxygen, and is dangerous for the cell because it induces the inactivation of various enzymes, lipid peroxidation and mutations. Superoxide dismutase can therefore be considered as a protective enzyme. The purpose of this work was to determine the level of superoxide dismutase activity in the Spanish population, and to study the factors that influence this activity. The superoxide dismutase activity of 2397 individuals was determined using the method described by Minami and Yoshikawa. The superoxide dismutase activity level in the adult Spanish population was found to be 4.16 +/- 0.89 Units/ml of blood. No significant variations with respect to sex were detected. But it was observed that the superoxide dismutase activity level was 9% higher in the young urban Spanish population.     

Superoxide dismutase activity in the Spanish population

Summary Superoxide dismutase is an enzyme that catalyzes the dismutation of superoxide radicals to hydrogen peroxide and molecular oxygen. This superoxide radical is produced by all aerobic cells as a normal metabolic intermediate of molecular oxygen, and is dangerous for the cell because it induces the inactivation of various enzymes, lipid peroxidation and mutations. Superoxide dismutase can therefore be considered as a protective enzyme. The purpose of this work was to determine the level of superoxide dismutase activity in the Spanish population, and to study the factors that influence this activity. The superoxide dismutase activity of 2397 individuals was determined using the method described by Minami and Yoshikawa. The superoxide dismutase activity level in the adult Spanish population was found to be 4.16±0.89 Units/ml of blood. No significant variations with respect to sex were detected. But it was observed that the superoxide dismutase activity level was 9% higher in the young urban Spanish population.     

Effects of chronic caffeine feeding on the activities of oxygen free radical defense enzymes in the growing rat heart and liver

The purpose of the present study was to determine the relationship between concentration of Zn, Cu and Fe, and the catalase, glutathione peroxidase and superoxide dismutase activities in the heart and liver of newborn rats whose dams were fed a diet supplemented with caffeine. Heart Zn levels of the 22- and 30-day-old rats of the caffeine group showed a decrease, whereas liver Zn levels showed an increase compared to the control. Cu levels in the liver at day 22 in the caffeine group were less than in the control. Cu- and Zn-containing superoxide dismutase activities showed an increase in the hearts of the caffeine group compared to the control. The activity of catalase and glutathion peroxidase showed no difference in the heart and liver between the groups. The present study suggests the possible involvement of superoxide dismutase enzyme in the impairment of heart formation as a result of chronic caffeine intake in the early growing period.     

Superoxide anion scavenging effect and superoxide dismutase activity of Ginkgo biloba extract

Ginkgo biloba extract is known to be efficient in diseases associated with free radical generation. The purpose of this work was to study, under in vitro conditions, the action of Ginkgo biloba extract (Gbe) against superoxide anion (O2-.), which is directly or indirectly implicated in cell damage. Gbe appears to have both an O2-. scavenging effect and also a superoxide dismutase activity. Its antiradical effect was demonstrated by low temperature electron spin resonance and in a non-enzymatic system (phenazine methosulfate-NADH), and its enzymatic activity was shown by polarographic determination.     

Superoxide dismutase activity in rabbit reticulocytes

Reticulocytosis was induced in rabbits by bleeding anemia and erythrocyte superoxide dismutase activity was determined. Reticulocytes were found to contain about 1.3 times as much activity as mature erythrocytes.     

Inhibition of paraquat phytotoxicity by a novel copper chelate with superoxide dismutating activity.

A chelate with superoxide dismutase activity, D-penicillamine copper complex, was shown to inhibit paraquat toxicity in flax cotyledons (Linum usitatissimum var. Reina). Paraquat-stimulated chlorophyll loss and ethane production were markedly reduced by this complex. The role of superoxide in the action of paraquat is briefly discussed.     

Superoxide dismutase activity in rabbit reticulocytes

Summary Reticulocytosis was induced in rabbits by bleeding anemia and erythrocyte superoxide dismutase activity was determined. Reticulocytes were found to contain about 1.3 times as much activity as mature erythrocytes.This work was supported in part by a Grant-in-Aid from the Japan Medical Research Foundation and a Grant-in-Aid (Project No. 56570363) from the Ministry of Education, Science and Culture of Japan.     

Role of oxygen radicals scavenging enzymes in the protoporphyrin induced photohemolysis

Inhibition of superoxide dismutase by diethyldithiocarbamate or cyanide increases the rate of red blood cells lysis after irradiation in the presence of protoporphyrin IX. Catalase activity, which is decreased during the photohemolytic process, appears to be not essential for the lytic event. No relationship between catalase activity and hemolysis rate was found. Superoxide dismutase appears to prevent only in part catalase inactivation by singlet oxygen.     

Selective effect of noradrenaline on superoxide dismutase activity in the brown adipose tissue and liver of the rat

Summary Noradrenaline treatment results in a significant increase of superoxide dismutase activity in the intrascapular brown adipose tissue but not in the liver.     

Role of oxygen radicals scavenging enzymes in the protoporphyrin induced photohemolysis

Summary Inhibition of superoxide dismutase by diethyldithiocarbamate or cyanide increases the rate of red blood cells lysis after irradiation in the presence of protoporphyrin IX. Catalase activity, which is decreased during the photohemolytic process, appears to be not essential for the lytic event. No relationship between catalase activity and hemolysis rate was found. Superoxide dismutase appears to prevent only in part catalase inactivation by singlet oxygen.     

Increase in superoxide dismutase activity induced by thyroid hormones in the brains of neonate and adult rats

Summary The activity of cytoplasmic superoxide dismutase (SOD) in the liver was about twice as high in adult rats as it was in neonates. In the brain and in the interscapular brown adipose tissue (IBAT), SOD activity was not changed during postnatal development, although it was slightly higher in the brain than in the IBAT (p>0.1). Thyroid hormones produced an increase in SOD activity in the brain of newborn rats, as well as in those animals 30 and 60 days old. The same quantity of hormones did not produce any significant changes in the liver or in the IBAT.     

Inactivation of superoxide dismutase by several thiocarbamic acid derivatives

Summary 4 thiocarbamic acid derivatives inhibited superoxide dismutase (SOD) activity in vitro. Dimethyldithiocarbamate also inhibited tissue SOD in mice in vivo. These data extend previously published results on the inhibitory action of diethyldithiocarbamate on SOD activity.Supported by the Clinical Research Center for the study of Parkinson's and Allied Diseases, Grant NS-05184 from the US Public Health Service.     

Glutathione peroxidase, superoxide dismutase and catalase in the red blood cells of GSH-normal and GSH-deficient sheep

Levels of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase were measured in the red blood cells of glutathione(GSH)-normal and GSH-deficient sheep. There were no significant differences in any of the 3 enzyme activities measured in the 2 groups of sheep. Also, there was no relationship between GSH level and the enzyme activity. These results suggest that inspite of large differences in GSH levels, the red blood cells from GSH-normal and GSH-deficient Merino sheep appear to have similar response to oxidative stress against which GSH is credited to play a major role.     

Inhibition of paraquat phytotoxicity by a novel copper chelate with superoxide dismutating activity

Summary A chelate with superoxide dismutase activity, D-penicillamine copper complex, was shown to inhibit paraquat toxicity in flax cotyledons (Linum usitatissimum var. Reina). Paraquat-stimulated chlorophyll loss and ethane production were markedly reduced by this complex. The role of superoxide in the action of paraquat is briefly discussed.This work was supported by grants from the German Academic Exchange Service to R.J. Youngman and by I.C.I. Ltd, Plant Protection Division.     

Differential influences of various arsenic compounds on glutathione redox status and antioxidative enzymes in porcine endothelial cells

The cellular response and detoxification mechanisms in porcine endothelial cells (PAECs) to arsenic trioxide (As2O3), sodium arsenite (NaAsO2) and sodium arsenate (Na2HAsO4) were investigated. NaAsO2 at 20 microM for 72 h increased Cu/Zn superoxide dismutase activity resulting in elevated intracellular hydrogen peroxide levels, but As2O3 and Na2HAsO4 did not. Trivalent arsenic compounds increased intracellular oxidized glutathione (GSSG) and total glutathione (GSH) and cellular glutathione peroxidase (cGPX) and glutathione S-transferase (GST) activity, but not glutathione reductase activity. The increased cGPX activity resulted in an elevated cellular GSSG content. Na2HAsO4 increased the cellular GSSG level at 72 h compared to controls. These results imply that the increased GSH content responding to the oxidative stress by trivalent arsenic compounds may be mainly related to the regulation of GSH turnover. The increased GST activity implies that the elevated intracellular GSH level responding to the oxidative stress may be used to conjugate arsenic in PAECs and facilitate arsenic efflux.     

Superoxide dismutase and life span ofDrosophila melanogaster

Summary Comparison of superoxide dismutase activity in homogenates of wild and vestigial strains ofD. melanogaster revealed a lower enzyme activity in the short-living vestigial strain.Acknowledgments. We are indebted to Prof. M. Olszewska for giving us fly specimens. This work was partly supported by the project No. R. III. 13. 2. 4.     

Hydrogen peroxide generation in Trypanosoma cruzi.

Homogenates from T. cruzi epimastigotes produced 3.4 pmoles H2O2/min 10(6) cells, as detected by the cytochrome c peroxidase assay. Addition of NADH or NADPH increased H2O2 production by a factor of 3 and 5, respectively. When supplemented with NADH and NADPH, the mitochondrial, microsomal and supernatant fractions produced H2O2, the soluble fraction and the mitochondrial membranes being apparently the main generators of H2O2. The epimastigote homogenates showed cyanide-sensitive superoxide dismutase activity, equivalent to 0.28 microgram bovine superoxide dismutase per mg homogenate protein.