Changes in iron metabolism and oxidative status in STZ-induced diabetic rats treated with bis(maltolato) oxovanadium(IV) as an antidiabetic agent

The role of vanadium as a micronutrient and hypoglycaemic agent has yet to be fully clarified. The present study was undertaken to investigate changes in the metabolism of iron and in antioxidant defences of diabetic STZ rats following treatment with vanadium. Four groups were examined: control; diabetic; diabetic treated with 1 mgV/day; and Diabetic treated with 3 mgV/day. The vanadium was supplied in drinking water as bis(maltolato) oxovanadium (IV) (BMOV). The experiment had a duration of five weeks. Iron was measured in food, faeces, urine, serum, muscle, kidney, liver, spleen, and femur. Superoxide dismutase, catalase, NAD(P)H: quinone-oxidoreductase-1 (NQO1) activity, and protein carbonyl group levels in the liver were determined. In the diabetic rats, higher levels of Fe absorbed, Fe content in kidney, muscle, and femur, and NQO1 activity were recorded, together with decreased catalase activity, in comparison with the control rats. In the rats treated with 3 mgV/day, there was a significant decrease in fasting glycaemia, Fe content in the liver, spleen, and heart, catalase activity, and levels of protein carbonyl groups in comparison with the diabetic group. In conclusion BMOV was a dose-dependent hypoglycaemic agent. Treatment with 3 mgV/day provoked increased Fe deposits in the tissues, which promoted a protein oxidative damage in the liver.The authors are grateful for support received from the Consejería de Innovación, Ciencia y Empresa, Andalusian Regional Government (Project P06-CTS-01435)

Oxidative Stress Mediates Physiological Costs of Begging in Magpie (Pica pica) Nestlings

[Background] Theoretical models predict that a cost is necessary to guarantee honesty in begging displays given by offspring to solicit food from their parents. There is evidence for begging costs in the form of a reduced growth rate and immunocompetence. Moreover, begging implies vigorous physical activity and attentiveness, which should increase metabolism and thus the releasing of pro-oxidant substances. Consequently, we predict that soliciting offspring incur a cost in terms of oxidative stress, and growth rate and immune response (processes that generate pro-oxidants substances) are reduced in order to maintain oxidative balance. [Methodology/Principal Findings] We test whether magpie (Pica pica) nestlings incur a cost in terms of oxidative stress when experimentally forced to beg intensively, and whether oxidative balance is maintained by reducing growth rate and immune response. Our results show that begging provokes oxidative stress, and that nestlings begging for longer bouts reduce growth and immune response, thereby maintaining their oxidative status. [Conclusions/Significance] These findings help explaining the physiological link between begging and its associated growth and immunocompetence costs, which seems to be mediated by oxidative stress. Our study is a unique example of the complex relationships between the intensity of a communicative display (begging), oxidative stress, and life-history traits directly linked to viability.GM-R was supported by the Spanish Government (Ministerio de Ciencia y Tecnología, “Juan de la Cierva” program), and TR was supported by the Consejo Superior de Investigaciones Científicas (CSIC; Proyectos Intramurales Especiales)

Selección parental y dieta como estrategias de atenuación del estrés crónico en la trucha Oncorhynchus mykiss (Walbaum, 1972)

Tesis Univ. Granada. Departamento de Biología Animal y Ecologí

Oxidative stress decreases with elevation in the lizard Psammodromus algirus

Oxidative stress is considered one of the main ecological and evolutionary forces. Several environmental stressors vary geographically and thus organisms inhabiting different sites face different oxidant environments. Nevertheless, there is scarce information about how oxidative damage and antioxidant defences vary geographically in animals. Here we study how oxidative stress varies from lowlands (300-700 m asl) to highlands (2200-2500 m asl) in the lizard Psammodromus algirus. To accomplish this, antioxidant enzymatic activity (catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione transferase, DT-diaphorase) and lipid peroxidation were assayed in tissue samples from the lizards' tail. Lipid peroxidation was higher in individuals from lowlands than from highlands, indicating higher oxidative stress in lowland lizards. These results suggest that environmental conditions are less oxidant at high elevations with respect to low ones. Therefore, our study shows that oxidative stress varies geographically, which should have important consequences for our understanding of geographic variation in physiology and life-history of organisms

Restricted Maximum Likelihood Estimation General Linear Mixed Model (REML-GLMM) showing the effect of treatment on concentration of malondialdehyde (MDA) as indicator of damage caused by oxidative stress, controlling for nest (random), date, mass gained and immune response to phytohaemagglutin.

<p>Restricted Maximum Likelihood Estimation General Linear Mixed Model (REML-GLMM) showing the effect of treatment on concentration of malondialdehyde (MDA) as indicator of damage caused by oxidative stress, controlling for nest (random), date, mass gained and immune response to phytohaemagglutin.</p

Mean ± SE for each variable measured in the study, and the effects of Treatment, controlling for Nest (random factor) and Date.

<p>A Restricted Maximum Likelihood Estimation General Linear Mixed Model (REML-GLMM) was used. <i>F</i>-values are shown. HB is for nestlings begging at a high level, and LB for nestlings begging at lower levels. Degrees of freedom were 1 for Treatment, and 18 for error. For time begging the analysis was performed after log-transformation, although raw data are shown. <i>P</i>-values: * for <i>P</i><0.05; ** for <i>P</i><0.01, and *** for <i>P</i><0.001, § for 0.05<<i>P</i><0.10, and ns for non significant.</p

Restricted Maximum Likelihood Estimation General Linear Mixed Model (REML-GLMM) showing the relationship between time begging and concentration of malondialdehyde (MDA) as indicator of damage caused by oxidative stress, controlling for nest (random), date, mass gained and immune response to phytohaemagglutin.

<p>Restricted Maximum Likelihood Estimation General Linear Mixed Model (REML-GLMM) showing the relationship between time begging and concentration of malondialdehyde (MDA) as indicator of damage caused by oxidative stress, controlling for nest (random), date, mass gained and immune response to phytohaemagglutin.</p