L-Ornithine



L-Ornithine is a non proteinogenic amino acid that primarily serves as a key intermediate in the urea cycle in living organisms. Its core functions are concentrated in nitrogen metabolism, liver detoxification, and various physiological regulation processes.

1. Core biochemical functions: urea cycle and ammonia detoxification
The most important role of L-ornithine is to participate in the urea cycle, which is the main pathway for mammals to convert toxic ammonia into non-toxic urea and excrete it from the body.

Ammonia clearance: In the liver, L-ornithine binds with carbamoyl phosphate to form citrulline, which then undergoes a series of reactions to ultimately produce arginine. Arginine is hydrolyzed to regenerate L-ornithine and release urea. This cyclic process effectively reduces the concentration of ammonia in the blood.
Clinical significance: Due to its key role in reducing blood ammonia, L-ornithine is often used in clinical practice in the form of L-ornithine L-aspartate (LOLA) to treat hepatic encephalopathy and hyperammonemia caused by cirrhosis. ‌‌