FCCC LOGO Faculty Publications
Kappler F , Su BY , Szwergold BS , Randall WC , Brown TR
Identification of galactitol 2-phosphate and galactitol 3- phosphate in the lens of galactose-fed rats
Metabolism-Clinical and Experimental. 1995 Dec;44(12) :1527-1531
PMID: ISI:A1995TL98200003   
Back to previous list
Production of unusual phosphorylated metabolites in the lens is one of several changes caused by hyperglycemia. Sorbitol 3- phosphate (Sor-3P) and fructose 3-phosphate (Fru-3P) are two such compounds identified in the diabetic lens, and galactitol 2-phosphate (Gal-2P) and galactitol 3-phosphate (Gal-3P) are identified here in the galactosemic lens. These new compounds are the first example of galactitol metabolism in mammalian tissue other than liver. Sor-BP and Fru-3P are also present in the galactosemic lens, apparently synthesized directly from their precursors, sorbitol and fructose, which are elevated in the lens due to increased flux of glucose through the aldose reductase (AR) pathway. The NADPH necessary to support this increased flux is derived from activation of the hexose monophosphate shunt (HMPS), which is clearly demonstrated by a large increase in the concentration of sedoheptulose 7- phosphate (Sed-7P), a HMPS-specific metabolite. Additionally, during 3 weeks of galactose feeding, there is a dramatic increase in lenticular concentrations of galactitol, sorbitol, galactose, and fructose and a sharp decrease in inositol. Glucose remains unchanged. A precipitous loss of both phosphorylated and nonphosphorylated metabolites occurs after 3 weeks, possibly due to lens rupture. Copyright (C) 1995 by W.B. Saunders Company
Times Cited: 2 English Article TL982 METABOLISM