In hyperglycemic condition (like diabetes) glycolysis enzyme hexokinase becomes saturated and the excess glucose enter into polyol / sorbitol pathway.
Sorbitol pathway (Polyol pathway)- It is a two step process.
Step 1. Glucose convert into sorbitol / polyol by aldose reductase.
Step 2. Sorbitol convert into fructose by sorbitol / polyol dehydrogenase.