The influence of calcium on glucose metabolism in the rabbit lens

Results were obtained which demonstrate that calcium accumulation in the rabbit lens may suppress glycolysis, not only by its inhibitory effect on cation transport but by its direct effect on glycolytic enzymes. In lenses cultured in calcium-enriched medium, lactate production declined in proportion to the increase in free and bound levels of calcium. In lens homogenates to which varying amounts of calcium were added, lactate production also decreased. To insure that excess calcium was not simply chelating ATP, homogenates were exposed to calcium and then dialyzed against a calcium-free buffer prior to addition of ATP. Under these conditions, lactate production diminished maximally by approximately 50% as bound calcium increased five-fold.