Effects of phospholine iodide on the metabolites of the glycolytic, pentose phosphate and sorbitol pathways in the rabbit lens.

Steady-state concentrations of the key intermediates from the glycolytic, pentose phosphate, and sorbitol pathways as well as the pyridine nucleotides were measured from the lens after 0.25% phospholine iodide had been instilled into rabbits' eyes twice a day for 18 weeks. In the lenses of those rabbits which had received treatment in both eyes fructose-1,6-diphosphate and pyruvate levels were increased, whereas 6-phosphogluconate, sorbitol and alpha-glycer0phosphate concentrations were decreased. alpha-Ketoglutarate and concentrations and ratios of NAD+ and NADH did not show any changes. In contrast, NADPH and total NADP concentrations as well as the NADPH/NADP+ ratio were decreased, and therefore total NAD/total NADP ratio increased after treatment. It appears that instillation of long-acting 0.25% phospholine iodide into rabbits' eyes results in increased glycolytic activity in the lens in response to the increased energy demand, wheras the activities of other metabolic pathways are suppressed.