Binding of selenium-75 to blood and liver cytosolic proteins in the preruminant calf

Trace element deficiencies in cattle

Deficiency of cobalt, copper, iron, iodine, manganese, selenium, or zinc can cause a reduction in production. Reduced production occurs most commonly when a deficiency corresponds to the phases of growth, reproduction, or lactation. Because of environmental, nutrient, disease, genetic, and drug interactions, deficiencies of single or multiple elements can occur even when the levels recommended by the National Research Council for these nutrients are being fed. Additionally, random supplementation of trace elements above National Research Council recommendations is not justified because of the negative interaction among nutrients and potential toxicosis. Evaluation of trace element status can be difficult because many disease states will alter blood analytes used to evaluate nutrient adequacy. Proper dietary and animal evaluation, as well as response to supplementation, are necessary before diagnosing a trace element deficiency.

Nickel-selenium interaction-time dependent biochemical alterations and metal decorporation in rats

The influence of selenium on the disposition of nickel and on Ni induced metallothionein levels was studied in female rats. Concomitant administration of Se (6.3 mumol/kg, intraperitoneally) and 63Ni (0.12 mmol/kg subcutaneously) lowered the Ni burden of all the soft organs and the plasma ceruloplasmin levels. Selenium caused no potentiating effect on the Ni induced hepatic MT. However, 3 days later, the lowered MT levels appeared related to the corresponding decrease in hepatic Ni content at day 6. The Ni selenide excretable complex and Ni-selenide protein complex appear to be probable mechanisms of the Ni-Se interaction in the present study.

Rat plasma selenoprotein P properties and purification

A selenoprotein in rat plasma, selenoprotein P, was fractionated and characterized. Plasma collected from rats 3 h post injection of 75SeO3(2-) contained one 75Se-labeled protein, selenoprotein P. Selenoprotein P was fractionated using salt precipitation, Affi-Gel Blue, and DEAE chromatography. The 75Se-containing subunit of selenoprotein P was purified to 90% homogeneity using SDS-polyacrylamide gel electrophoresis followed by electroelution. This isolation resulted in an 850-fold purification of the 75Se-containing subunit of selenoprotein P with a 15% yield of 75Se radioactivity. The molecular weight of selenoprotein P in plasma was 98,000. The 75Se-containing subunit of selenoprotein P had a molecular mass of 57 kDa as determined by SDS-polyacrylamide gel electrophoresis. Isoelectric focusing under nondenaturing conditions resulted in a band of 75Se radioactivity at pH 5.4. A comparison of Coomassie Blue- and silver-staining properties of selenoprotein P in SDS-polyacrylamide gels was made. Reverse-phase HPLC and Sephadex G-50 chromatography of tryptic peptides of the 57 kDa subunit of selenoprotein P yielded several peaks of 75Se radioactivity. These results indicate that 75Se is present in several locations within the 57 kDa subunit of selenoprotein P.