Medicine & USMLE

Sorbitol (Polyol) Pathway

Biochemical Pathways
  1. Glycolysis
  2. Citric Acid Cycle (TCA Cycle)
  3. Electron Transport Chain (ETC)
  4. Cori Cycle
  5. De Novo Purine Synthesis
  6. De Novo Pyrimidine Synthesis
  7. Purine Salvage
  8. Purine Excretion
  9. Ethanol Metabolism
  10. Pyruvate Metabolism
  11. HMP Shunt (Pentose Phosphate Pathway)
  12. Galactose Metabolism
  13. Sorbitol (Polyol) Pathway
  14. Urea Cycle
  15. Alanine (Cahill) Cycle
  16. Catecholamine Synthesis & Breakdown
  17. Homocysteine Metabolism
  18. Fatty Acid Synthesis (Citrate Shuttle)
  19. Fatty Acid Breakdown (Carnitine Shuttle)
  20. Propionic Acid Pathway
  21. Fructose Metabolism
  22. Regulation by Fructose-2,6-Bisphosphate (F-2,6-BP)
  23. Glycogenesis
  24. Glycogenolysis

The Sorbitol Pathway, also called the Polyol Pathway, is a two-step process that converts glucose to fructose. The pathway contributes to diabetic complications affecting the eyes, kidneys, and nerves.

First, glucose is converted into sorbitol, in a reaction catalyzed by aldose reductase. This reaction also uses NADPH, producing NADP+ in the process.

Second, sorbitol is converted into fructose by sorbitol dehydrogenase. This reaction produces NADH from NAD+ in the process.

Deficiencies in sorbitol dehydrogenase activity cause sorbitol accumulation in high glucose states, such as in diabetes mellitus. The major tissues with poor sorbitol dehydrogenase activity are the lens, retina, kidney, and schwann cells of the peripheral nervous system. Sorbitol accumulation contributes to cataracts, retinopathy, renal failure, and peripheral neuropathy, respectively.

Find this Sorbitol (Polyol) Pathway mnemonic and more Biochemical Pathways mnemonics among Pixorize's visual mnemonics for the USMLE Step 1 and NBME Shelf Exams.