ORGANOPHOSPHATES OF THE CRYSTALLINE LENS - A NUCLEAR MAGNETIC-RESONANCE SPECTROSCOPIC STUDY

Abstract

The concentrations of the principal organophosphate metabolites present in the intact crystalline rabbit lens was quantitated, the intralens pH was measured and the dynamic changes during 24 h incubations was evaluated by P-31 NMR spectroscopy. Tissue perchloric acid extracts prepared from these same lenses were analyzed by this technique to verify metabolite identifications and to quantitate the concentrations of the minor lens metabolites. Values for lens organophosphate concentrations, including 3 groups of previously unidentified P-containing substances, were established for freshly excised lenses, 24 h incubated lenses and lenses incubated in glucose-deficient media. Lens metabolite levels were not adversely affected by incubation in a medium previously shown to maintain lens clarity and ion transport capabilities. Lens incubation in glucose-deficient media induced significant metabolic changes characterized by a time-dependent decline in ATP, corresponding increases in ADP, PI and phosphorylated hexoses. Cataract formation was noted after incubation in this medium. Apparently, alterations in the organophosphate levels of the lens actually precede changes in the Na+ and K+ concentrations and therefore may be the initiating factor in formation of lens cataracts.