Effects of vitamin B-6 deficiency on selenium metabolism in the rat.
Rats were fed for 23 d diets adequate or deficient in vitamin B-6 and containing selenium as either sodium selenite, selenocysteine (SeCys) or selenomethionine (SeMet). They were then injected with 75Se of the same chemical form and killed 2 d later. Tissue deposition of stable and radiotracer selenium and the activity of glutathione peroxidase (GSHPx) were used to assess selenium utilization. Erythrocyte levels of selenium and GSHPx were lower in vitamin B-6--deficient animals for all forms of selenium; however, 75Se deposition in erythrocytes was not affected by vitamin B-6 status. The activities of cystathionine lyase, aspartate aminotransferase and selenocysteine lyase were lower in livers of vitamin B-6--deficient rats than in vitamin B-6--supplemented rats. The proportion of liver and kidney 75Se soluble in 5% trichloroacetic acid and 0.1 M 2-mercaptoethanol was consistently lower in vitamin B-6--deficient animals, but cation-exchange chromatography of tissue extracts did not identify a specific low-molecular-weight species. Tissue retention of 75Se provided as SeMet was increased in vitamin B-6--deficient animals, but the proportion of 75Se retained in muscle and liver as SeCys was significantly reduced. These findings suggest that the conversion of SeMet to a form available for GSHPx synthesis is reduced by vitamin B-6 deficiency.
Beilstein
M A
MA
Department of Agricultural Chemistry, Oregon State University, Corvallis 97331.
Whanger
P D
PD
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002852:Chromatography, Ion Exchange; D004912:Erythrocytes / Q000032:analysis; D005979:Glutathione Peroxidase / Q000302:isolation & purification; D006868:Hydrolysis; D007668:Kidney / Q000032:analysis; D008099:Liver / Q000032:analysis / Q000201:enzymology / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000032:analysis; D011485:Protein Binding; D011736:Pyridoxine / Q000008:administration & dosage / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012643:Selenium / Q000032:analysis / Q000378:metabolism*; D026681:Vitamin B 6 Deficiency / Q000378:metabolism*
D000596:Amino Acids; D005979:Glutathione Peroxidase; D012643:Selenium; D011736:Pyridoxine