INVESTIGATIONS INTO THE LOSS OF GLUTATHIONE FROM LENSES IN ORGAN-CULTURE

Purpose. To investigate possible causes and implications of the decrea se in glutathione concentration in rat lenses during organ culture. Me thods. Freshly excised lenses were incubated in modified TC-199 medium . Ellman's Reagent or the GSH-400 assay were used to assay glutathione levels in lenses cultured for different times and under a variety of altered culture conditions. Results. In lenses from young rats the glu tathione decrease was not ameliorated by reduction of oxygen tension i n the incubator, nor by supplementation of the culture medium with var ious antioxidants or sulfhydryl compounds, nor with the amino acid pre cursors of glutathione. Addition of 2-mercaptoethanol stimulated cyste ine transport into the lens but had only a modest effect in maintainin g the level of glutathione. The decrease in glutathione concentration was less in cultured lenses from older rats. Lenses from rhesus monkey s exhibited no decrease in glutathione levels when maintained in organ culture for up to 48 h. Conclusions. The basis for the decreased glut athione in cultured young rat lenses is still uncertain. The data from the present study indicate a definite relationship between glutathion e loss and age for cultured rat lenses, with young lenses being much m ore susceptible. The resistance of cultured monkey lenses to loss of g lutathione demonstrates species differences in this property which may be relevant to previously reported differences in susceptibility to o xidative damage.