METABOLISM OF [SE-75] SELENITE BY RHESUS-MONKEYS

The metabolism of [75Se]selenite was studied in rhesus monkeys. In blood samples taken various times after injection, Sephadex G-150 gel filtration revealed that the majority of the 75Se was associated with hemoglobin and low-MW compounds in erythrocytes up to 24 h after Se injection. Subsequently a gradual increase of 75Se occurred in glutathione peroxidase (GSH-Px) with a concurrent decrease of label with hemoglobin. In contrast to the erythrocytes, over 80% of the labeled Se in plasma was associated with 1 peak 3 h and later after injection. This major protein eluted at a position similar to GSH-Px on gel filtration, but subsequent chromatography on diethylaminoethyl (DEAE)-Sephacel separated the radiolabeled protein from GSH-Px. Gel filtration of heart, muscle, brain and pancreas cytosol revealed 2 major selenium-containing proteins, whereas 1 was predominant in liver and kidney. The major selenium peak was associated with GSH-Px in liver but not in the kidney. GSH-Px activity with either organic or inorganic peroxides as substrates and glutathione transferase activity were higher in liver than kidney.