POLYOL AND WATER ACCUMULATION IN MUSCLE OF GALACTOSE-FED RATS

Skeletal muscle contains high levels of aldose reductase that catalyze s the reduction of galactose to the polyol galactitol. Galactitol and water were measured in muscle of rats fed a high galactose diet with o r without addition of the aldose reductase inhibitor sorbinil. Galacti tol, measured in isolated samples of muscle by HPLC, reached steady-st ate levers (5.9 +/- 1.0 mg/g tissue) within 3 days. Muscle water, dete rmined in vivo by magnetic resonance imaging, increased (51 +/- 5%, P < 0.02) to steady-state levels within 7 days. Both the increased galac titol and water remained constant for the 4-month duration of this stu dy. Aldose reductase activity also remained constant. Sorbinil prevent ed both the increase in galactitol and the increase in water. These re sults suggest that the increase in water is due to the osmotic effects of galactitol accumulation and demonstrate that galactitol and water accumulation neither up-regulate nor down-regulate aldose reductase ex pression in skeletal muscle,