Dietary selenium intake controls rat plasma selenoprotein P concentration.
The purpose of this study was to determine the effect of dietary selenium on selenoprotein P concentration. Selenoprotein P was quantitated in plasma by radioimmunoassay. Selenium-dependent glutathione peroxidase activity in plasma and liver 105,000 x g supernatant was measured for comparison. Weanling male rats were fed a selenium-deficient diet or a control diet that contained 0.5 mg selenium/kg as Na2SeO4. The concentration of selenoprotein P fell at approximately the same rate in the rats fed the selenium-deficient diet as did plasma glutathione peroxidase activity. Groups of weanling rats were fed different levels of selenium for 8 wk. Selenoprotein P concentration was proportional to dietary selenium level up to 0.1 mg/kg and was a greater percentage of control values than was glutathione peroxidase activity. No increment in selenoprotein P concentration occurred between 0.1 and 0.5 mg selenium/kg diet. These results indicate that the concentration of selenoprotein P in the plasma is directly dependent on selenium supply in the diet up to 0.1 mg/kg. There is overlap between the dietary selenium ranges in which selenoprotein P concentration and glutathione peroxidase activity increase, but the selenoprotein P range is lower than the glutathione peroxidase range.
Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232.
J G
JG
Yang
K E
KE
Hill
R F
RF
Burk
D000284:Administration, Oral; D000818:Animals; D005979:Glutathione Peroxidase / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D008715:Methionine / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D012643:Selenium / Q000097:blood; D051149:Selenoprotein P; D051140:Selenoproteins
D011506:Proteins; D051149:Selenoprotein P; D051140:Selenoproteins; D008715:Methionine; D005979:Glutathione Peroxidase; D012643:Selenium