13C NMR spectroscopic measurement of glutathione synthesis and antioxidant metabolism in the intact ocular lens.

A 13C NMR spectroscopic method for non-invasive, time-resolved measurements of glutathione function in the intact ocular lens maintained in organ culture is described. L-[beta-13C]cysteine (1 mM) included in the incubation medium is incorporated, by way of lenticular amino acid uptake and glutathione biosynthetic mechanisms, into the cysteinyl residue of intralenticular glutathione. 13C-NMR chemical shift measurements facilitate analysis of glutathione synthesis and anti-oxidant reactions in the intact tissue. The results of this preliminary study demonstrate the viability of a rapid non-invasive method for monitoring the multiple aspects of glutathione biosynthesis, metabolism, and function in intact tissue.