The further metabolism of sorbitol-3-phosphate and fructose-3-phosphate in the mature rat lens.
Glucose and phosphorus metabolism in mature (8-month-old) rat lenses were examined with NMR spectroscopy. Nondiabetic mature lenses contained sorbitol-3-phosphate (S3P) and fructose-3-phosphate (F3P) which were absent from young (1- to 2-month-old) normal rat lenses. The concentrations of these two phosphates can be changed through (1) diabetes induction with streptozotocin - this results in a dramatic increase in both compounds; and (2) oral dosing with a drug known to prevent sorbitol production - both metabolites disappeared. When normal mature lenses were incubated in 35.5 mM 13C1-glucose, both 13C1-lactate and 13C3-lactate were produced. Preservation of the 13C label at C1 is likely through the formation of 13C1-S3P and -F3P, which were then split through an aldolase-like mechanism into two 3-carbon compounds, one an unlabeled glycerol and the other 13C1-alpha-glycerophosphate (from S3P) and 13C1-dihydroxyacetone phosphate (from F3P). These reactions can contribute to the increase in alpha-glycerophosphate observed in both the streptozotocin-induced diabetic lenses and lenses incubated in high glucose.
Cheng
H M
HM
NMR Research, Howe Laboratory of Ophthalmology, Harvard Medical School, Boston, Mass., USA.
Cheng
F Y
FY
Xiong
H
H
Xiong
J
J
D000375:Aging / Q000378:metabolism*; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism; D005636:Fructosephosphates / Q000378:metabolism*; D006600:Hexosephosphates / Q000378:metabolism*; D007908:Lens, Crystalline / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values
D005636:Fructosephosphates; D006600:Hexosephosphates; C059844:sorbitol 3-phosphate; C062519:fructose 3-phosphate