scholarly journals Comparison of Whole-Blood Glutathione Peroxidase Activity, Levels of Serum Selenium, and Lipid Peroxidation in Subjects from the Fishing and Rural Communities of "Rabo de Peixe" Village, San Miguel Island, The Azores' Archipelago, Portugal

2003 ◽  
Vol 92 (1) ◽  
pp. 27-40 ◽  
Author(s):  
M. L. Pavão ◽  
C. Cordeiro ◽  
A. Costa ◽  
J. A. Raposo ◽  
M. C. Santos ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Rural Communities ◽  
Glutathione Peroxidase ◽  
Peroxidase Activity ◽  
Whole Blood ◽  
Serum Selenium ◽  
Activity Levels ◽  
Glutathione Peroxidase Activity ◽  
Azores Archipelago ◽  
San Miguel Island

Low Selenium Status in the Elderly Influences Thyroid Hormones

1995 ◽  
Vol 89 (6) ◽  
pp. 637-642 ◽  
Author(s):  
Oliviero Olivieri ◽  
Domenico Girelli ◽  
Margherita Azzini ◽  
Anna Maria Stanzial ◽  
Carla Russo ◽  
...  
Keyword(s):  
Glutathione Peroxidase ◽  
Thyroid Hormones ◽  
Peroxidase Activity ◽  
Controlled Trial ◽  
The Elderly ◽  
Serum Selenium ◽  
Selenium Status ◽  
Glutathione Peroxidase Activity ◽  
Double Blind ◽  
Double Blind Placebo

1. Iodothyronine 5′-deiodinase, which is mainly responsible for peripheral triiodothyronine (T3) production, has recently been demonstrated to be a selenium-containing enzyme. In the elderly, reduced peripheral conversion of thyroxine (T4) to T3 and overt hypothyroidism are frequently observed. 2. We measured serum selenium and erythrocyte glutathione peroxidase (as indices of selenium status), thyroid hormones and thyroid-stimulating hormone in 109 healthy euthyroid subjects (52 women, 57 men), carefully selected to exclude abnormally low thyroid hormone levels induced by acute or chronic diseases or calorie restriction. The subjects were subdivided into three age groups. To avoid conditions of undernutrition or malnutrition, dietary records were obtained for a sample of 24 subjects, randomly selected and representative of the whole population for age and sex. 3. In order to properly assess the influence of selenium status on iodothyronine 5′-deiodinase type I activity, a double-blind placebo-controlled trial was also carried out on 36 elderly subjects, resident at a privately owned nursing home. 4. In the free-living population, a progressive reduction of the T3/T4 ratio (due to increased T4 levels) and of selenium and erythrocyte glutathione peroxidase activity was observed with advancing age. A highly significant linear correlation between T4, T3/T4 and selenium was observed in the population as a whole (for T4, R = −0.312, P < 0.002; for T3/T4 ratio, R = 0.32, P < 0.01) and in older subjects (for T4, R = −0.40, P < 0.05; for T3/T4 ratio, R = 0.54, P < 0.002). 5. The main result of the double-blind placebo-controlled trial was a significant improvement of selenium indices and a decrease in the T4 level in selenium-treated subjects; serum selenium, erythrocyte glutathione peroxidase activity and thyroid hormones did not change in placebo-treated subjects. 6. We concluded that selenium status influences thyroid hormones in the elderly, mainly modulating T4 levels.

Whole blood glutathione peroxidase activity in melanoma patients

1999 ◽  
Vol 144 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Marı́a Rosa Ros-Bullón ◽  
Paloma Sánchez-Pedreño ◽  
José Hilario Martı́nez-Liarte
Keyword(s):  
Glutathione Peroxidase ◽  
Peroxidase Activity ◽  
Whole Blood ◽  
Glutathione Peroxidase Activity ◽  
Melanoma Patients

scholarly journals Effects of estrogens and androgens on erythrocyte antioxidant superoxide dismutase, catalase and glutathione peroxidase activities during the menstrual cycle

2000 ◽  
Vol 167 (3) ◽  
pp. 447-452 ◽  
Author(s):  
C Massafra ◽  
D Gioia ◽  
C De Felice ◽  
E Picciolini ◽  
V De Leo ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Menstrual Cycle ◽  
Glutathione Peroxidase ◽  
Peroxidase Activity ◽  
Free Testosterone ◽  
Cycle Phase ◽  
Activity Levels ◽  
Glutathione Peroxidase Activity ◽  
Antioxidant Enzyme System ◽  
Peroxidase Enzyme

The effects of physiological changes in estrogens and androgens on the erythrocyte antioxidant superoxide dismutase, catalase and glutathione peroxidase enzyme activities during the menstrual cycle were investigated in healthy eumenorrheic women. Blood samples were taken on alternate days from twelve normally cyclic women (age range: 20 to 27 years; mean age: 24.1 years) from the first day of one menstrual cycle until the first day of the subsequent one. Plasma was analyzed for FSH, LH, estradiol, progesterone, testosterone, free testosterone and androstenedione concentrations. Erythrocyte superoxide dismutase, catalase and glutathione peroxidase activities were evaluated on the same days and cycle length was standardized on the basis of the preovulatory estradiol peak. Significant cyclic phase-related changes were observed in glutathione peroxidase (P<0.05), with higher glutathione peroxidase activity levels from the late follicular to the early luteal phase compared with those found in the early follicular phase (P<0.001 and P<0.002 respectively). A significant positive correlation was observed between mean estradiol and glutathione peroxidase cycle-related variations (r=0.80, P<0.001), whereas no significant cycle phase-dependent changes were seen in superoxide dismutase and catalase. No effect of progesterone and androgens on the erythrocyte antioxidant enzyme system was documented. The findings indicate that physiological ovarian estradiol production during the menstrual cycle may have an important role in regulating erythrocyte glutathione peroxidase activity.

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