Glutathione peroxidase and selenium in sheep. II.* The relationship between glutathione peroxidase and selenium-responsive unthriftiness in Merino lambs

1979 ◽  
Vol 30 (4) ◽  
pp. 703 ◽  
Author(s):  
DI Paynter ◽  
JW Anderson ◽  
JW McDonald

Low erythrocyte activities of the selenium-containing enzyme glutathione peroxidase were found in Merino lambs in an area of the Strathbogie Ranges in central Victoria where selenium-responsive conditions have previously been reported. Body weight gain trials conducted over 10 properties in the above area demonstrated that the severity of selenium-responsive unthriftiness was significantly correlated with the erythrocyte glutathione peroxidase activity (r = – 0.95, P <: 0.001). Positive body weight responses to selenium treatment were only observed in lambs with erythrocyte glutathione peroxidase activities less than 30 U/g Hb prior to selenium treatment. These findings indicate that measurement of erythrocyte glutathione peroxidase activity provides a convenient index of the selenium status in sheep. ________________ *Part I, Aust. J. Agric. Res., 30: 695 (1979).

1995 ◽  
Vol 89 (6) ◽  
pp. 637-642 ◽  
Author(s):  
Oliviero Olivieri ◽  
Domenico Girelli ◽  
Margherita Azzini ◽  
Anna Maria Stanzial ◽  
Carla Russo ◽  
...  

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.


1959 ◽  
Vol 37 (1) ◽  
pp. 763-774
Author(s):  
Dorothy S. Dow ◽  
C. E. Allen

Rate of body weight gain of both the young chick and the young rat was markedly inhibited following ingestion of amounts of thyroxine which were greatly in excess of physiological requirements. The rate of body weight gain of the young rat was also markedly inhibited in alloxan diabetes. The administration of insulin partly or largely prevented the observed effect on body weight in both conditions. The administration of thyroxine caused a reduction of rat skeletal muscle mass which was partially prevented when insulin was given concurrently with thyroxine.Reduced body weight gain and muscle mass in the rat were accompanied by marked increases in the muscle DNA and nuclei concentration. Nuclear diameter and the amount of DNA per nucleus remained unchanged. RNA concentration of the muscle was not reduced. The beneficial effect of insulin administration on body weight and muscle mass was accompanied by a preventive effect against changes in muscle DNA and nuclei concentration. However, since the DNA content of muscle bundles remained relatively unchanged and since muscle bundle weights changed proportionately with body weight it would appear that DNA content does not reflect change in muscle mass.The effectiveness of insulin in the thyroxine-treated animal appears to be due to an improved utilization of energy. A hypoglycemic action of thyroxine implies an antagonism between the two hormones in their mechanism of action. The relationship between the two hormones is not direct since the administration of insulin does not affect the increased plasma protein-bound iodine levels resulting from thyroxine treatment.


2010 ◽  
Vol 79 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Mária Weber ◽  
Krisztián Balogh ◽  
Judit Fodor ◽  
Márta Erdélyi ◽  
Zsolt Ancsin ◽  
...  

The effect of T-2 and HT-2 toxin using different doses in the starter (0-21 days: 1.04 mg T-2 toxin and 0.49 mg HT-2 toxin kg-1feed), and finisher diets (22-39 days: 0.12 mg T-2 toxin and 0.02 mg HT-2 toxin kg-1feed) was investigated in broiler chickens. Birds were divided into two groups fed with control and T-2 and HT-2 toxin contaminated diets. Pathological signs of toxicity were investigated on days 21 and 39 of the trial, individual liveweight was measured weekly. Five birds from each group were sacrificed on the 21st and 39th days of treatment, when blood plasma, red blood cell, liver and kidney samples were taken, in which malondialdehyde and reduced glutathione concentration and glutathione-peroxidase activity were determined. Pathological signs (lesions in the oral cavity and on the tongue, inflammation in the small intestine) were found in the group fed T-2 and HT-2 toxin contaminated feed on day 21 compared to control. Body weight was significantly lower as a result of feeding T-2 and HT-2 toxin contaminated diet. However, the contamination did not cause a significant increase of malondialdehyde content in the analysed tissues. Reduced glutathione content was significantly lower in the liver homogenate on day 39 than that of the control. Glutathione peroxidase activity also did not differ significantly in blood plasma, red blood cell haemolysates and kidney homogenates, while it was significantly higher in the liver homogenates of the mycotoxin-challenged birds. In conclusion, it can be stated that T-2 and HT-2 toxin exposure has long-term effects in broiler chickens.


1979 ◽  
Vol 32 (5) ◽  
pp. 451 ◽  
Author(s):  
JF Wilkins

A high correlation was observed between HzOz-induced oxidation of haemoglobin and glutathione peroxidase activity in whole blood samples from sheep. A role of this enzyme in the prevention of oxidative damage to the erythrocyte and its contents has been previously demonstrated. The possibility of using haemoglobin oxidation in whole blood as an alternative assessment of glutathione peroxidase activity and hence of selenium status is proposed.


2012 ◽  
Vol 32 (6) ◽  
pp. 403-407 ◽  
Author(s):  
Cristiane Cominetti ◽  
Maritsa C. de Bortoli ◽  
Arthur B. Garrido ◽  
Silvia M.F. Cozzolino

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