Changes in rat lens proteins and glutathione reductase activity with advancing age

We examined the changes in the amounts of water-soluble and water-insoluble proteins of rat lenses, and in glutathione reductase activity and glutathione reductase gene expression, with advancing age. The lens total protein increased in 1-month-old rats, 3-month-old rats, and 6-month-old rats, but thereafter decreased in 12-month-old-rats. The water-soluble proteins decreased with advancing age, while the water-insoluble proteins increased. The glutathione reductase activity decreased with advancing age, but the decreased glutathione reductase activity almost recovered by addition of flavin adenine dinucleotide (FAD) in vitro. However, advancing age had no effect on the level of mRNA for glutathione reductase.