Citrulline
Citrulline, an amino acid. Non-proteinogenic AA — urea-cycle intermediate generated from ornithine + carbamoyl phosphate (OTC). Found free in… Oral half-life 1 h.
Non-proteinogenic AA — urea-cycle intermediate generated from ornithine + carbamoyl phosphate (OTC). Found free in watermelon (Citrullus). Clinically superior to oral Arginine for raising sustained plasma arginine because citrulline is not a substrate for intestinal/hepatic arginase — it bypasses first-pass metabolism and is recycled to arginine in kidney via argininosuccinate synthase (ASS) and argininosuccinate lyase (ASL). The resulting arginine supports endothelial NOS → NO (see Nitric oxide synthesis) → vasodilation. Also used diagnostically (citrulline generation test) as an enterocyte-mass biomarker.
Pharmacokinetics
- Oral — t½ 1 h · F 80% · ka 1.3 h⁻¹ · Vd 24.5 L
Related compounds
- Arginine — synergistic
Sources: PMID:17662090