Motivaciones, significados y riesgos en los encuentros sexuales de hombres gays de La Ciudad Autónoma de Buenos Aires en el contexto del covid-19 / Motivations, meanings and risk in gay men sexual encounters in the Ciudad Autonoma de Buenos Aires in the context of covid-19 / Motivações, significados e riscos nos encontros sexuais de homens gays na Cidade Autônoma de Buenos Aires no contexto do covid-19

Resumen Se buscó identificar las motivaciones que llevan a los hombres gay del AMBA (Área Metropolitana de Buenos Aires) a romper el Aislamiento Preventivo Social Obligatorio (APSO) con fines de encuentro sexual en el contexto de la pandemia de covid-19. Se realizó un estudio cualitativo-exploratorio, con veinte entrevistas semiestructuradas a igual número de personas. La muestra fue intencional no representativa, el contacto se estableció mediante la aplicación de GRINDR y TINDER pactando las entrevistas de manera telefónica o presencial. Se encontró que los entrevistados habían roto la cuarentena motivados principalmente por "la calentura", la dificultad para mantener "la abstinencia sexual" y por las "ganas de tener sexo", en el contexto de una alta valoración personal de la libertad y de familiaridad con la clandestinidad. Algunos realizan medidas de disminución del riesgo de covid-19, como el uso de cubrebocas y alcohol en gel, otros consideran que no son población en riesgo.

Abstract We aimed to identify the motivations of gay men on the AMBA to break the governmental policy of Obligatory Preventive Social Isolation (APSO) with the purpose of sexual encounter. We designed a qualitative-exploratory study, where twenty semi-structured interviews were applied to equal number of gay men. The sample was intentional and not representative, the contact was established through the application of GRINDER and TINDER arranging the interviews by telephone or in person. We found that interviewees have broken quarantine mainly motivated by "the fever", the difficulty of keeping the "abstinence", and the "desire to have sex", in the context or a highly personal value of freedom and the familiarity with clandestine behavior. Some took measures to lower the risk of covid-19, by using covered mouths and alcohol-based gel, others mentioned that they are not part of a risk group.

Resumo Buscou-se identificar as motivações que levam homens gays da AMBA (Área Metropolitana de Buenos Aires) a romper o Isolamento Social Preventivo Obrigatório (APSO) para fins de encontros sexuais no contexto da pandemia covid-19. Realizou-se um estudo qualitativo-exploratório, com vinte entrevistas semi estruturadas com o mesmo número de pessoas. A amostra foi intencional não representativa, o contato foi estabelecido por meio dos aplicativos GRINDR e TINDER, agendando as entrevistas por telefone ou pessoalmente. Constatou-se que os entrevistados romperam a quarentena motivados principalmente pelo «tesão¼, pela dificuldade de manter a «abstinência sexual¼ e pelo «desejo de fazer sexo¼, no contexto de uma alta valorização pessoal da liberdade e de familiaridade com a clandestinidade. Alguns relataram medidas para reduzir o risco de COVID 19, como o uso de máscaras e álcool em gel, outros consideram que não são população de risco.

Protective effect exerted by soil phosphorus on soybean subjected to arsenic and fluoride.

Objetive: Arsenic (As) and fluoride (F) are found in groundwater and soils around the world, causing different problems to crops. Because these elements compete against phosphorus (P) in soils and plants, their relationship is complex. The aim of this work was to study the oxidative stress of soybean plants subjected to different concentrations of As and F, and the effect of P. METHODS: The following 10 treatments were carried out in each of two soils with different P content: three As levels (low 10 mg As kg-1, medium 50 mg As kg-1 and high 100 mg As kg-1), three F levels (low 160 mg F kg-1, medium 250 mg F kg-1 and high 500 mg F kg-1) and three As + F levels (same concentrations), and the control treatment (soil with the background As and F concentrations) Lipid peroxidation, chlorophyll, gluthatione contents and antioxidant enzymes activities were determination. RESULTS: Increased lipid peroxidation and alterations in glutathione content, catalase, superoxide dismutase and peroxidase activities as well as in chlorophyll content revealed that As causes higher oxidative stress in plants grown in soils with low P content. CONCLUSION: Stress parameters in F treatments were less affected. Plants grown in soils enriched with P revealed a decrease in the toxic effects caused by As and F.

Indole acetic acid is responsible for protection against oxidative stress caused by drought in soybean plants: the role of heme oxygenase induction.

Objectives This study was focused on the role of indole acetic acid (IAA) in the defense against oxidative stress damage caused by drought in soybean plants and to elucidate whether heme oxygenase-1 (HO-1) and nitric oxide (NO) are involved in this mechanism. IAA is an auxin that participates in many plant processes including oxidative stress defense, but to the best of our knowledge no information is yet available about its possible action in drought stress. Methods To this end, soybean plants were treated with 8% polyethylene glycol (PEG) or 100 µM IAA. To evaluate the behavior of IAA, plants were pretreated with this compound previous to PEG addition. Lipid peroxidation levels (thiobarbituric acid reactive substances (TBARS)), glutathione (GSH) and ascorbate (AS) contents, catalase (CAT), superoxide dismutase (SOD), and guaiacol peroxidase (POD) activities were determined to evaluate oxidative damage. Results Drought treatment (8% PEG) caused a significant increase in TBARS levels as well as a marked decrease in the non-enzymatic (GSH and AS) and enzymatic (CAT, SOD, and POD) antioxidant defense systems. Pre-treatment with IAA prevented the alterations of stress parameters caused by drought, while treatment with IAA alone did not produce changes in TBARS levels, or GSH and AS contents. Moreover, the activities of the classical enzymes involved in the enzymatic defense system (SOD, CAT, and POD) remained similar to control values. Furthermore, this hormone could enhance HO-1 activity (75% with respect to controls), and this increase was positively correlated with protein content as well as gene expression. The direct participation of HO-1 as an antioxidant enzyme was established by performing experiments in the presence of Zn-protoporphyrin IX, a well-known irreversible inhibitor of this enzyme. It was also demonstrated that HO-1 is modulated by NO, as shown by experiments performed in the presence of an NO donor (sodium nitroprusside), an NO scavenger (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), or an NO synthesis inhibitor (N-nitro-l-arginine methyl ester, NAME). Discussion It is concluded that IAA is responsible, at least in part, for the protection against oxidative stress caused by drought in soybean plants through the modulation of NO levels which, in turn, enhances HO-1 synthesis and activity.

The role of salicylic acid in the prevention of oxidative stress elicited by cadmium in soybean plants.

The protective action of salicylic acid (SA) pre-treatment on soybean plants before cadmium (Cd) addition was tested. Oxidative stress parameters, such as TBARS formation, glutathione and chlorophyll content, were altered by Cd, instead no differences were observed in plants only pre-treated with SA. Antioxidant enzymes were affected by Cd treatment, while SA protected against these effects. These findings indicated that SA could act as a protector against oxidative stress induced by Cd. Taking into account the fact that heme-oxygenase-1 (HO-1) has been previously described as a novel antioxidant enzyme, experiments were carried out to determine whether it was involved in the protection exerted by SA. As expected, Cd brought about an enhancement of 57 % in HO-1 activity and 150 % in protein content (150 %), SA also increased both the enzyme activity and its protein content (28 and 75 %, respectively). Surprisingly, the observed rise of HO activity and protein content under SA treatment was lower than that produced by Cd alone. These lower values indicated, that HO-1 could not be directly involved in the protection of SA against Cd effects. In order to shed light in the mechanisms involved in SA effects, Cd content was determined in the tissues of Cd treated plants with and without SA pre-treatment. Results indicated that, in the presence of SA, Cd uptake was inhibited, thus avoiding its deleterious effects. Moreover, the observed HO-1 activity enhancement by SA indicates that this phytohormone could be engaged in the signalling pathway of heme degradation.

The role of 5-aminolevulinic acid in the response to cold stress in soybean plants.

In this study, the possibility of enhancing cold stress tolerance of soybean plants (Glycine max L.) by exogenous application of 5-aminolevulinic acid (ALA) was investigated. ALA was added to the Hoagland solution at various concentrations ranging from 0 to 40 µM for 12 h. After ALA treatment, the plants were subjected to cold stress at 4°C for 48 h. ALA at low concentrations (5-10 µM) provided significant protection against cold stress compared to non-ALA-treated plants, enhancing chlorophyll content (Chl) as well as relative water content (RWC). Increase of thiobarbituric acid reactive species (TBARS) levels was also prevented, whereas exposure to higher ALA concentrations (15-40 µM) brought about a dose dependent increase of these species, reaching a maximum of 117% in plants pre-treated with 40 µM ALA compared to controls. ALA pre-treatment also enhanced catalase (CAT) and heme oxygenase-1 (HO-1) activities. These findings indicate that HO-1 acts not only as the rate limiting enzyme in heme catabolism, but also as an antioxidant enzyme. The highest cold tolerance was obtained with 5 µM ALA pre-treatment. Results show that ALA, which is considered as an endogenous plant growth regulator, could be used effectively to protect soybean plants from the damaging effects of cold stress by enhancing the activity of heme proteins, e.g., catalase (CAT) and by promoting heme catabolism leading to the production of the highly antioxidant biliverdin and carbon monoxide, without any adverse effect on the plant growth.

Heme Oxygenase Contributes to Alleviate Salinity Damage in Glycine max L. Leaves.

Plants are frequently subjected to different kinds of stress, such as salinity and, like other organisms, they have evolved strategies for preventing and repairing cellular damage caused by salt stress. Glycine max L. plants were subjected to different NaCl concentrations (0-200 mM) for 10 days. Treatments with 100 and 200 mM NaCl induced ion leakage and lipid peroxidation augmentation, loss in chlorophyll content, and accumulation of O(2) (*-) and H(2)O(2). However, 50 mM NaCl did not modify these parameters, which remains similar to control values. Catalase, superoxide dismutase, and heme oxygenase (HO-1) activities and gene expressions were increased under 100 mM NaCl, while no differences were observed with respect to controls under 50 mM salt. Treatment with 200 mM NaCl caused a diminution in the enzyme activities and gene expressions. Results here reported let us conclude that HO also plays a leading role in the defense mechanisms against salinity.

Angiotensin II regulates cardiac hypertrophy via oxidative stress but not antioxidant enzyme activities in experimental renovascular hypertension.

The aim of this study was to provide new insights into the role of angiotensin II and arterial pressure in the regulation of antioxidant enzyme activities in a renovascular model of cardiac hypertrophy. For this purpose, aortic coarcted rats were treated with losartan or minoxidil for 7 days. Angiotensin II induced cardiac hypertrophy and oxidative stress via Nox4, p22(phox) and p47(phox), which are components of the NAD(P)H oxidase. Antioxidant enzymes were regulated by arterial pressure and were not implicated in cardiac hypertrophy. Heme oxygenase-1, the rate-limiting enzyme in heme catabolism, behaved as a catalase and glutathione peroxidase, and is regulated by arterial pressure. In summary, the present report indicates that cardiac hypertrophy, induced by renovascular hypertension, depends on angiotensin II through reactive oxygen species and is not prevented by the action of antioxidant enzymes.

Heme oxygenase and catalase gene expression in nodules and roots of soybean plants subjected to cadmium stress.

Heme oxygenase (HO, EC 1.14.99.3) catalyses the oxidative conversion of heme to biliverdin IX alpha (BV) with the concomitant released of carbon monoxide and iron. Recently, plant HOs have been involved in the defence mechanism against oxidative stress. The goal of this study was to evaluate the time-course of HO-1 and catalase (CAT, EC 1.11.1.6) gene expressions in nodules and roots of soybean plants subjected to Cd treatment. No significant changes were observed up to 24 h. After 48 h of 200 microM Cd exposure, an up-regulation of HO-1 mRNA (110%) occurred in nodules. On the other hand, a down-regulation was found in roots (39%). While there was an augmentation in CAT transcript levels (30%) in nodules, an important diminution (52%) was evidenced in roots. Changes observed in gene expression were also found in protein levels and activities. These data suggest that an induction of CAT and HO-1 occurred in nodules as a response of cell protection against oxidative damage. However, after 72 h treatment, a down-regulation of HO-1 mRNA was found either in nodules or in roots (78% and 94%, respectively), while a similar response was evidenced for CAT (40% and 83%, respectively). These results are consistent with our previous findings suggesting that oxidative stress produced by Cd were more pronounced in roots than in nodules of soybean plants. Moreover, this behaviour could explain the major viability observed in nodules respect to roots, and provide a new insight into the processes involved in the antioxidant defence system in plant tissues.

The effect of nitric oxide on heme oxygenase gene expression in soybean leaves.

Heme oxygenase (HO, EC 1.14.99.3) catalyzes the oxidative conversion of heme to biliverdin IXalpha with the concomitant release of carbon monoxide and iron. Recently, HO has been involved in the protection against oxidative stress in plants. The fact that nitric oxide (NO), an endogenous signaling molecule in animals and plants mediates responses to abiotic and biotic stresses, prompted us to study whether this molecule could modulate HO-1 gene transcription. To fulfill this objective leaves of soybean (Glycine max L.) plants were stimulated with Cd, employing an acute intoxication model. Cadmium caused dehydration, chlorophyll loss and ion leakage. Semi-quantitative RT-PCR analysis showed no augmentation of HO-1 transcript levels with respect to controls. Pretreatment with 100 microM sodium nitroprussiate (SNP), a well-known NO donor, prevented the effects caused by Cd. When the HO-1 mRNA levels were analyzed, a significant augmentation (54%) was observed with respect to Cd-treated plants. On the other hand, 50 or 300 microM SNP did not fully prevent the effects elicited by Cd. When HO-1 transcript levels were analyzed, no significant enhancement or a down-regulation was observed. The potassium salt of 2-(4-carboxylphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), a specific NO scavenger, arrested NO-mediated protective effects against to Cd-induced oxidative damage. These data provide an understanding of one of the possible roles that NO can play against an oxidative insult. NO is cytoprotective depending on its concentration, and it was further demonstrated that this protection could be, at least in part, mediated by an enhancement of HO-1 mRNA, as it happens with genes associated with the antioxidant defense system.

Cadmium induced oxidative stress in soybean plants also by the accumulation of delta-aminolevulinic acid.

Cadmium toxicity has been extensively studied in plants, however its biochemical mechanism of action has not yet been well established. To fulfil this objective, four-weeks-old soybean nodulated plants were treated with 200 muM Cd(2+) for 48 h. delta-aminolevulinic acid dehydratase (ALA-D, E.C. 4.2.1.24) activity and protein expression, as well as delta-aminolevulinic acid (ALA) and porphobilinogen (PBG) concentrations were determined in nodules, roots and leaves. In vitro experiments carried out in leaves were performed using leaf discs to evaluate the oxidant and antioxidant properties of ALA and S-adenosyl-L: -methinone (SAM), respectively. Oxidative stress parameters such as thiobarbituric acid reactive substances (TBARS) and GSH levels as well as superoxide dismutase (SOD, E.C. 1.15.1.1), and guaiacol peroxidase (GPOX, E.C. 1.11.1.7) were also determined. Cadmium treatment caused 100% inhibition of ALA-D activity in roots and leaves, and 72% inhibition in nodules whereas protein expression remained unaltered in the three studied tissues. Plants accumulated ALA in nodules (46%), roots (2.5-fold) and leaves (104%), respect to controls. From in vitro experiments using leaf discs, exposed to ALA or Cd(2+), it was found that TBARS levels were enhanced, while GSH content and SOD and GPOX activities and expressions were diminished. The protective role of SAM against oxidative stress generated by Cd(2+) and ALA was also demonstrated. Data presented in this paper let us to suggest that accumulation of ALA in nodules, roots and leaves of soybean plants due to treatment with Cd(2+) is highly responsible for oxidative stress generation in these tissues.

Heme oxygenase up-regulation in ultraviolet-B irradiated soybean plants involves reactive oxygen species.

Ultraviolet-B (UV-B) radiation has a negative impact on plant cells, and leads to the generation of reactive oxygen species (ROS). Heme oxygenase (HO, EC 1.14.99.3) plays a protective role against oxidative stress in mammals, but little is known about this issue in plants. Here, we report for the first time the response of HO in leaves of soybean (Glycine max L.) plants subjected to UV-B radiation. Under 7.5 and 15 kJ m(-2 )UV-B doses, HO, catalase (CAT, EC 1.11.1.6) and ascorbate peroxidase (APX, EC 1.11.1.11) activities were increased and the production of thiobarbituric acid reactive substances (TBARS) regain control values after 4 h of plant recuperation. Treatment with 30 kJ m(-2) UV-B provoked a decrease in these antioxidant enzyme activities. Immunoblot analysis showed a 4.3 and 3.7-fold increase in HO-1 protein expression after irradiation with 7.5 and 15 kJ m(-2), respectively. HO-1 transcript levels were enhanced (up to 77%) at these doses, as assessed by semi-quantitative RT-PCR. These data demonstrated that increased HO activity was associated with augmented protein expression and transcript levels. Plants pre-treated with the antioxidant ascorbic acid did not show the UV-B-induced up-regulation of HO-1 mRNA, but hydrogen peroxide treatment could mimic this reaction. Our results indicate that HO is up-regulated in a dose-depending manner as a mechanism of cell protection against oxidative damage and that such response occurred as a consequence of HO-1 mRNA enhancement involving ROS.

Involvement of heme oxygenase as antioxidant defense in soybean nodules.

OBJECTIVE: We have previously demonstrated that the inducible form of heme oxygenase plays a critical role in protecting against oxidative stress in mammals. To gain further insight into the functions of this enzyme in plants, we have tested its activity and expression in soybean nodules subjected to cadmium (Cd) stress. MATERIALS AND METHODS: Four-weeks-old soybean nodulated plants were treated with different cadmium chloride concentrations (0, 50 and during 48 h. Oxidative stress parameters such as TBARS content, GSH levels and antioxidant enzyme activities were measured as well as heme oxygenase activity and expression. Besides, the effect of biliverdin and Zn-protophorphyrin IX were analyzed. RESULTS: Treatment with 200 microM Cd during 48 h caused a 67% increase in TBARS content, whereas GSH decreased 44%, and total superoxide dismutase, gluthatione reductase and guaiacol peroxidase were also inhibited 54, 20 and 60%, respectively. A total of Cd produced the overexpression of heme oxygenase-1, as well as a 10-fold enhancement of its activity. Co-administration of biliverdin (10 microM) completely prevented the effects caused by Cd. Treatment with Zn protoporphyrin IX, a strong inhibitor of heme oxygenase, expectedly decreased heme oxygenase-1 activity to half. When the inhibitor was given together with Cd, completely prevented the enzyme induction and oxidative stress parameters were significantly enhanced. CONCLUSION: Taking together, these results are indicating that heme oxygenase plays a protective role against oxidative cell damage in soybean nodules.

Heme oxygenase exerts a protective role against oxidative stress in soybean leaves.

We have previously demonstrated that the induction of heme oxygenase-1 (EC 1.14.99.3) plays a protective role for mammalian cells against oxidative stress. Here, we investigated for the first time the possible role of heme oxygenase-1 as an antioxidant defense in leaves of soybean plants. Treatment with 200 microM Cd during 48 h caused a 70% increase in thiobarbituric acid reactive substances, whereas GSH decreased 67%, guaiacol peroxidase and total superoxide dismutase also inhibited 49% and 46%, respectively. Two hundred micromolar of Cd produced the overexpression of heme oxygenase-1, as well as a 4.5-fold enhancement of its activity. Administration of biliverdin partially prevented the effects caused by Cd. Pretreatment with Zn protoporphyrin IX, a potent inhibitor of heme oxygenase, expectedly decreased heme oxygenase-1 activity to half. When the inhibitor was given before Cd, it completely prevented the enzyme induction increasing the levels of oxidative stress parameters. Collectively, these results indicated that although plant heme oxygenases share little homology to heme oxygenases from non-plant species, they also play an important protective role against oxidative cell damage.

Bilirubin is highly effective in preventing in vivo delta-aminolevulinic acid-induced oxidative cell damage.

Delta-aminolevulinic acid (ALA), precursor of heme, accumulates in a number of organs, particularly in liver of patients with acute porphyrias or lead intoxication. This study characterizes the involvement of bilirubin as an antioxidant in a chronic intoxication with ALA. Female Wistar rats were injected intraperitoneally a daily dose of 40 mg ALA/body wt., during 10 days. A marked increase in lipid peroxidation and a decrease in GSH content were observed 24 h after the last injection of ALA. The activities of liver antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase were also diminished. ALA synthase (ALA-S) and heme oxygenase-1 were induced. Both ALA dehydratase (ALA-D) and porphobilinogenase (PBG-ase) activities were inhibited. Administration of bilirubin (5 mmol/kg body wt.) 2 h before ALA treatment entirely prevented the effects of ALA. Co-administration of ALA and Sn-protoporphyrin IX (Sn-PPIX; 100 microg/body wt., i.p.), a potent inhibitor of heme oxygenase, completely abolished its induction and provoked a marked decrease in liver GSH levels as well as an increase in lipid peroxidation. These results add further support to the proposal assigning bilirubin a key protective role against oxidative damage here induced by ALA.

Paraquat-generated oxidative stress in rat liver induces heme oxygenase-1 and aminolevulinic acid synthase.

The in vivo effect of the known herbicide, paraquat, on both hepatic oxidative stress and heme metabolism was studied. A marked increase in lipid peroxidation and a decrease in reduced glutathione (GSH) content were observed 1 h after paraquat administration. The activity of liver antioxidant enzymes, superoxide dismutase, catalase and glutathione peroxidase was decreased 3 h after paraquat injection. Heme oxygenase-1 induction started 9 h after treatment, peaking at 15 h. delta-aminolevulinic acid synthase induction occurred once heme oxygenase had been enhanced, reaching its maximum (1.5-fold of control) at 16 h. delta-aminolevulinic acid dehydratase activity was 40% inhibited at 3 h showing a profile similar to that of GSH, while porphobilinogenase activity was not modified along the whole period of the assay. Administration of alpha-tocopherol (35 mmol/kg body weight) 2 h before paraquat treatment entirely prevented the increase in thiobarbituric acid reactive substances (TBARS) content, the decrease in GSH levels as well as heme oxygenase-1 and delta-aminolevulinic acid synthase induction. This study shows that oxidative stress produced by paraquat leads to an increase in delta-aminolevulinic acid synthase and heme oxygenase-1 activities, indicating that the herbicide affects both heme biosynthesis and degradation.

Rat kidney porphobilinogen deaminase kinetics. Detection of enzyme-substrate complexes.

BACKGROUND AND AIMS: Acute intermittent porphyria (AIP) is an inherited disease resulting from a reduced activity of the enzyme porphobilinogen deaminase (PBG-D). The kidney is an important target for numerous porphyrinogenic drugs and it may contribute to the clinical manifestations of porphyric attacks. An evaluation of kidney PBG-D role in the AIP pathophysiology requires detailed information on kidney PBG-D properties, under normal conditions. METHODS: Rat kidney PBG-D was purified to homogeneity and initial reaction velocities were calculated by measuring uroporphyrinogen I formation at pH 8.2 for different incubation times (0-20 min) and over a wide range of substrate concentrations (0.8-66 microM). RESULTS: Purified rat kidney PBG-D is a monomeric enzyme showing only a single protein band after SDS-PAGE, Western blot and isoelectric focusing (pI 4.9). Its molecular mass is 40 +/- 2.3 kDa, determined by SDS-PAGE and 39.8 +/- 2 kDa by gel filtration chromatography. Rat kidney PBG-D has an unusual kinetic behaviour, exhibiting a deviation from the Michaelis-Menten hyperbola. PBG-D kinetic data required a fitting to an equation of higher degree, leading to the following apparent kinetic constants: K(1) = 2.08 +/- 0.01 microM and K(2) = 0.102 +/- 0.003 microM. CONCLUSION: The values of these constants fulfil the restriction 4K(2) < or = K(1)(2), necessary for the occurrence of isoenzymes, interpreted in this work as enzyme-substrate intermediates. The initial reaction velocity expression here defined, correlates with an enzyme carrying only one active site but allowing, through conformational changes, the detection of at least two enzyme-substrate intermediates formed during PBG-D reaction.

Angiotensin-(1-7) stimulates oxidative stress in rat kidney.

The effect of two different doses of angiotensin-(1-7) and angiotensin II on the oxidative stress generation was analyzed in rat kidney. Animals were injected intraperitoneally with a single dose of angiotensin-(1-7) or angiotensin II (20 or 50 nmol/kg body weight) and killed 3 h after injection. Production of thiobarbituric acid reactive substances (TBARS), measured as indicator of oxidative stress induction, was significantly increased in rat kidney after Ang-(1-7) administration up to 30% and 50% over controls, at 20 and 50 nmol/kg, respectively. Reduced glutathione (GSH), the most important soluble antioxidant defense in mammalian cells, showed a significant decrease of 13% and 20% at 20 and 50 nmol/kg of angiotensin-(1-7), respectively. When the antioxidant enzyme activities were determined, it was found that catalase activity was not altered by the assayed angiotensin-(1-7) doses while superoxide dismutase and glutathione peroxidase activities were significantly reduced by injection of 20 nmol/kg (34% and 13%, with respect to controls) and 50 nmol/kg of angiotensin-(1-7) (54% and 22%, respectively). In contrast, angiotensin II injections did not produce significant changes neither in TBARS levels nor in soluble and enzymatic defense parameters at the two doses used in this work. These results suggest that angiotensin-(1-7) is undoubtedly related to oxidative stress induction.