Uptake of(75)Se in cataractous rat lens proteins.

The purpose of the present study was to measure the pattern of uptake of(75)Se into proteins in normal rat lenses and into the proteins of lenses with selenite-induced cataract. Ten-day-old suckling rats received a single injection of(75)Se with or without a cataractous dose of cold carrier sodium selenite. Four days after injection, the proteins from excised lenses were counted for(75)Se radioactivity and subjected to gel permeation chromatography, amino acid analyses, and mass spectrometry. All three soluble crystallin lens proteins took up(75)Se in both normal and cataractous lenses. However, cataractous lenses did not take up(75)Se into a soluble protein in which major quantities of(75)Se were taken up in normal rats. Futhermore,(75)Se in the gamma-crystallins was associated with an unusual acidic amino acid. It was concluded that selenium metabolism by lens proteins may be unusual compared to other soft tissues.