Transport of Circulating Reduced Glutathione at the Basolateral Side of the Anterior Lens Epithelium: Physiologic Importance and Manipulations

Transport of circulating reduced glutathione (GSH) was studied at the basolateral side of the lens epithelium by using an in situ vascular eye perfusion technique in guinea-pigs with rapid sampling to ensure detecting initial uptakes. The unidirectional transport rates of [ 35S ]-GSH (4n m) from plasma and aqueous into the epithelial cytosol were 0.046 ±0.003 and 6.88 ±0.39min -1, respectively. HPLC analysis indicated that over 94% of [ 35S ]-GSH remained intact in the epithelium and cortex in the presence or absence of γ-glutamyl transpeptidase inhibitor, serine borate. Simultaneous infusion of [ 35S-cysteine ]-GSH and [ 3H-glycine ]-GSH confirmed the non-involvement of γ-glutamyl transpeptidase in GSH transport across the lenticular membranes by showing that 35S / 3H ratio in the epithelium and cortex was the same as in the aqueous and plasma. GSH epithelial influx was reduced by 53% ( P