Studies on selenium incorporation into, and electron-transfer function of, liver microsomal fractions from normal and vitamin E-deficient rats given phenobarbitone.
1. The incorporation of (75)Se from Na(2) (75)SeO(3) into the liver endoplasmic reticulum of rats given phenobarbitone was investigated by using a zonal centrifuge technique. 2. It was found that, in rats deprived of vitamin E, or of vitamin E and selenium, phenobarbitone was without effect on the incorporation of (75)Se or on its conversion to (75)Se(2-). When vitamin E was given at the same time as the phenobarbitone and (75)Se, there was a large increase in the amount of (75)Se and (75)Se(2-) found in the smooth reticulum. It is concluded that there may be a specific vitamin E-dependent role for selenium and selenide in the smooth endoplasmic reticulum, and it is suggested, in the light of these and other observations, that the selenide may form a part of the active centre of a non-haem iron-containing protein ;X', that may function in microsomal electron transport. 3. Measurements of the contents of cytochromes P-450 and b(5) in liver microsomal fractions of rats given vitamin E-deficient, and vitamin E- and selenium-deficient diets, showed that haemoprotein biosynthesis is unimpaired in these rats and phenobarbitone treatment resulted in the expected increase in the haemoproteins. 4. When the reduction of cytochrome P-450 by NADH and NADPH was measured, no difference was found between normal and deficient animals. 5. These results are discussed in relation to current knowledge of microsomal electron transfer.
D000818:Animals; D001798:Blood Proteins / Q000096:biosynthesis; D002501:Centrifugation, Zonal; D003577:Cytochrome P-450 Enzyme System; D003580:Cytochromes; D004579:Electron Transport; D004721:Endoplasmic Reticulum / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D009243:NAD; D009249:NADP; D010084:Oxidation-Reduction; D010634:Phenobarbital / Q000494:pharmacology*; D011506:Proteins; D011868:Radioisotopes; D051381:Rats; D012643:Selenium / Q000378:metabolism*; D014811:Vitamin E Deficiency / Q000378:metabolism*
D001798:Blood Proteins; D003580:Cytochromes; D011506:Proteins; D011868:Radioisotopes; D009243:NAD; D009249:NADP; D003577:Cytochrome P-450 Enzyme System; D012643:Selenium; D010634:Phenobarbital