Subcellular distribution of selenium in the liver from rats fed selenium from fish: selenocystine and inorganic selenite.

Four groups of rats of a normal selenium status were given different selenium compounds during a long-term feeding experiment (28 days). The selenium supplementations (per kg diet) were sodium selenite (1 mg), selenocystine (2 mg), and two different concentration levels of selenium from fish (0.1 and 1 mg). Differential pelleting of liver homogenates demonstrated that selenium was present in all the subcellular fractions, with a recovery of 55-60% in the cytosols. Gel permeation high-performance liquid chromatography of the cytosol fractions demonstrated the presence of protein-bound selenium at a molecular weight of 70,000 daltons. The subcellular distributions as well as the protein binding of selenium in the cytosols were identical in all dietary groups. This indicates a similar long-term liver metabolism of the four selenium compounds tested in the rat.