Tissue-specific functions of individual glutathione peroxidases.

The selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) changes its physical characteristics and biological functions during sperm maturation PHGPx exists as a soluble peroxidase in spermatids but persists in mature spermatozoa as an enzymatically inactive, oxidatively cross-linked, insoluble protein In the midpiece of mature spermatozoa, PHGPx protein represents at least 50 percent of the capsule material that embeds the helix of mitochondria The role of PHGPx as a structural protein may explain the mechanical instability of the mitochondrial midpiece that is observed in selenium deficiency

https://science.sciencemag.org/content/sci/285/5432/1393.full.pdf

Dual Function of the Selenoprotein PHGPx During Sperm Maturation

Recent identification of new selenocysteine-containing proteins has revealed relationships between the two trace elements selenium (Se) and iodine and the hormone network. Several selenoproteins participate in the protection of thyrocytes from damage by H(2)O(2) produced for thyroid hormone biosynthesis. Iodothyronine deiodinases are selenoproteins contributing to systemic or local thyroid hormone homeostasis. The Se content in endocrine tissues (thyroid, adrenals, pituitary, testes, ovary) is higher than in many other organs. Nutritional Se depletion results in retention, whereas Se repletion is followed by a rapid accumulation of Se in endocrine tissues, reproductive organs, and the brain. Selenoproteins such as thioredoxin reductases constitute the link between the Se metabolism and the regulation of transcription by redox sensitive ligand-modulated nuclear hormone receptors. Hormones and growth factors regulate the expression of selenoproteins and, conversely, Se supply modulates hormone actions. Selenoproteins are involved in bone metabolism as well as functions of the endocrine pancreas and adrenal glands. Furthermore, spermatogenesis depends on adequate Se supply, whereas Se excess may impair ovarian function. Comparative analysis of the genomes of several life forms reveals that higher mammals contain a limited number of identical genes encoding newly detected selenocysteine-containing proteins.

/pdf/selenium-the-thyroid-and-the-endocrine-system-whj7p9hkjb.pdf

Selenium, the Thyroid, and the Endocrine System

Selenium Drives a Transcriptional Adaptive Program to Block Ferroptosis and Treat Stroke.

s, 61: 4784 (1964). 5. MONIER-WILLIAMS, G. W. A/umimum in food. London, Ministry of Health, 1935 (Reports on Public Health and Medical Subjects). 6. SYLVESTER, R. 0. ET AL. Factors involved in the locatiOn and operation of an aluminium reduction plant. Proceedings of the 22nd Industrial Waste Conference. Lafayette, IN, Purdue University, 1967, pp. 441-454. 7. RIDGWAY, J. ET AL. Water quality changes-chemical and microbiological studies. In: Water distrzbution systems. Medmenham, England, Water Research Centre, 1979. 8. AINSWORTH, R. G. ET AL. Deposits, corrosion products and corrosion mechanisms in iron mains. In: Water distribution systems. Medmenham, England, Water Research Centre, 1979. 9. AINSWORTH, R. G. ET AL. The introduction of new water mto old distribution systems. Medmenham, England, Water Research Centre, 1980 (TR 146). 10. VozAR, L. Content of aluminium in the diet and its biological action. Voprosy pitanija, 21: 28 (1962). II. ZooK, E. G. & LEHMANN, J. Total diet study: content of ten minerals-aluminium, calcium, phosphorus, sodium, potassium, boron, copper, iron, manganese and magnesium. Journal of the AssociatiOn of Official Agricultural Chemists, 48: 850 (1965). 12. GABOVICH, R. D.

https://www.jstage.jst.go.jp/article/jhs1956/35/5/35_5_307/_pdf

WHO guidelines for drinking-water quality.

Selenium retention in tissues and sperm of rats fed a Torula yeast diet.

Influence of Dietary and Injected Selenium on Whole-body Retention, Route of Excretion, and Tissue Retention of 75SeO32- in the Rat

SummaryTwo peaks of protein-bound 75Se are seen on the gel filtration chromatogram of rat plasma when the rat has been fed a 0.5 ppm selenium diet and no NaCl is added to the Tris-HCl elution buffer. One of those peaks is absent from the plasma of rats fed a very low selenium diet. Poly-acrylamide gel electrophoresis of the 75Se peaks suggests that each may have more than one protein component. Dialysis studies indicate that the 75Se is not in the form of selenotrisulfides.

Effect of Dietary Selenium Level on 75Se Binding to Rat Plasma Proteins

SummaryRadioselenium studies in rats utilizing whole-body counting and determination of urinary and fecal 75Se indicate the existence of a threshold dietary level of selenium above which urinary excretion of selenium is directly related to its dietary level and below which it is not. The threshold lies between 0.054 and 0.084 ppm for the forms of selenium used here. Tissue distribution of 75Se was markedly different in all groups and exhibited no threshold under the conditions of this experiment.

Selenium: dietary threshold for urinary excretion in the rat.

: Plasma was obtained from 14 normal people after an overnight fast and the standard lipoprotein classes were separated in the ultracentrifuge. Protein, triglycerides, cholesterol, phospholipids, and alpha-tocopherol were determined on each lipoprotein and plasma sample. Alpha-tocopherol was found in all lipoprotein classes. Alpha-tocopherol level correlated best with total lipids (r=0.855), phospholipids (r=0.801), and cholesterol (r=0.795). Poor correlations were obtained with triglycerides (r=0.317) and proetin (r=0.368). Two subjects who were taking supplementary alpha-tocopherol were also studied and their alpha-tocopherol values were higher but distribution among lipoprotein classes was similar. (Author)

Raymond F. Burk

Papers

Selenium retention in tissues and sperm of rats fed a Torula yeast diet.

Influence of Dietary and Injected Selenium on Whole-body Retention, Route of Excretion, and Tissue Retention of 75SeO32- in the Rat

Effect of Dietary Selenium Level on 75Se Binding to Rat Plasma Proteins

Selenium: dietary threshold for urinary excretion in the rat.

Distribution of alpha Tocopherol in Human Plasma Lipoproteins