Uptake and retention of selenite and selenomethionine in cultured K-562 cells

The selenium uptake and retention have been studied in K-562 cells exposed to selenite or selenomethionine. In the uptake experiments the cells were e xposed to two doses of selenite (5 or 50 muM) or selenomethionine (10 or 50 muM). In the retention study the cells were treated for 2 h with the above mentioned doses of the selenocompounds before being observed at different times. The selenium uptake in cells exposed to selenite 5 muM began to satu rate at 8 h, but increased again between 48 and 96 h. In cells exposed to s elenite 50 muM the selenium uptake never reached a maximum, however, at 48 and 96 h the cell viability decreased strongly. The two doses of selenite s howed different retention patterns, with a relatively small cellular decrea se of selenium after treatment with selenite 5 muM compared to treatment wi th 50 muM of selenite. The selenium uptake in cells exposed to selenomethio nine 10 muM or selenomethionine 50 muM began to saturate at 24 h and 48 h, respectively. The retention patterns were similar for both selenomethionine doses with a continuous decrease of the selenium concentration during the whole observation period. The results indicated a more controlled uptake an d retention pattern of selenomethionine compared to selenite.