The effects of age on phosphatic metabolites of the human crystalline lens

Abstract

Paired human lenses ranging from 2 to 96 yr old ( n = 17) were harvested within 2 hr post-mortem and immersed in liquid nitrogen. Phosphorus containing metabolites from perchloric acid extracts were quantitated using phosphorus-31 nuclear magnetic resonance spectroscopy. Low-energy metabolites detected include the phosphomonoesters (PME) hexose-6 phosphate, α-glycerol phosphate, fructose 1,6-diphosphate, β-glycerol phosphate (β-GP), uncharacterized phosphomonoesters at 4·63 δ, 4·34 δ and 3·05 δ, phosphorylethanolamine (PE), inosine and adenosine monophosphates, and phosphorylcholine (PC). Inorganic orthophosphate (Pi), glucose 1-phosphate and glycerol 3-phosphorylcholine were the other low-energy metabolites detected. High-energy metabolites phosphocreatine (PCr), adenosine tri- and di-phosphates (ATP, ADP), nucleoside diphosphorylsugars (NS) and the dinucleotides were also detected. The following metabolic indices were calculated: PCr Pi , PME Pi ; ATP Pi , PCr ATP , ATP ADP , PE+PC, PC PE , energy charge, phosphorylation potential, and the energy modulus. A significant linear increase with age ( P < 0·05) occurred only in the uncharacterized resonance at 3·05 δ ( r = 0·4593). Significant linear decreases with age ( P < 0·05) occurred in the uncharacterized resonance at 4·63 δ ( r = −0·5950), β-GP ( r = −0·5018), PCr ( r = −0·4495), n.s. ( r = −0·4882). There was a significant ( P < 0·05) linear decrease in the energy modulus (ratio of high-energy to low-energy metabolites).