Abstract:
The objective of our study was to investigate the effect of selenium on
selenoprotein W. Western blot analysis indicated that selenoprotein W is present in
muscle, brain, testis and spleen of rat tissues. Tissue distribution of selenoprotein W
was not altered in rats fed various selenium levels. Among muscle, brain, testis and
spleen, selenoprotein W in muscle was most responsive to selenium status, but brain
appeared to be the least responsive organ. Northern blot data indicated that
selenoprotein W mRNA in rat muscle increased significantly as levels of selenium
supplementation increased. Western blot data indicate that selenoprotein W in rat
muscle is non-detectable until selenium supplementation increased to 0.06 ppm, and
the level of selenoprotein W in muscle reached a plateau at 1 ppm selenium
supplementation where no further increase occurred. Except brain, selenoprotein W
was higher in all tissues in sheep fed a selenium supplemented diet than in those fed
the deficient diet. However, selenoprotein W levels were not different in brains
between selenium-deficient and selenium-supplemented sheep. In contrast to rats,
selenoprotein W was as high in the heart as in the muscle of selenium-supplemented
sheep.
In the study with L8 muscle cells, selenoprotein W did not change significantly
during cell differentiation, indicating that selenoprotein W was not affected by muscle
cell differentiation. Selenite was the most effective form of selenium for selenoprotein
W synthesis in these muscle cells. Selenoprotein W level reached a plateau when L8
myotubes were incubated with 10⁻⁷ M selenium, whereas selenoprotein W mRNA
reached a plateau with 10⁻⁸ M selenium.
