Citrulline

Citruline: an amino acid at the heart of several physiological mechanisms

The citrulline, also called THE-citrulline, is a non-proteinogenic amino acid. This means that it is not used directly to manufacture the body's proteins, unlike many other amino acids.

It intervenes in particular in the urea cycle and in the metabolism of arginine. Naturally present in some foods, it is also used as an ingredient in different formulations of food supplements.

What is the role of citrulline in the body ?

Citruline intervenes in several metabolic processes. Its role is particularly known in the urea cycle, a mechanism that allows the body to transform ammonia from the metabolism of nitrogen into urea, then eliminated by the kidneys.

Citruline and urea cycle

In this cycle, the citulline is an intermediate step between different nitrogen molecules. This physiological process is essential for the management of nitrogen in the body.

The transformation into arginine

The circulating citruline can be converted into arginine, especially at the renal level. Arginine then participates in several metabolic pathways, including that allowing the synthesis of nitric oxide (NO). This relationship explains why these two amino acids are often studied together.

Where is the citrulline ?

The watermelon is particularly known for its natural content in citulline. This is present in its flesh and in some other parts of the fruit, with variable quantities according to the variety and the conditions of culture.

The body also produces citrulline, especially from the intestinal metabolism of other amino acids. Food intake and endogenous production thus contribute to its presence in the body.