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L-arginine is a precursor for nitrate biosynthesis in humans
C D Leaf1, J S Wishnok, S R Tannenbaum
1Division of Toxicology, Whitaker College, Cambridge, Massachusetts 02139.
Biochemical and Biophysical Research Communications
|September 15, 1989
Summary
L-arginine, a nitrogen source, is converted into urinary nitrate in humans. This study confirms L-arginine as a precursor for endogenous nitrate synthesis in people.
Area of Science:
- Biochemistry
- Human Physiology
- Metabolic Pathways
Background:
- Nitrate is an important molecule in human physiology.
- L-arginine is known to be a nitrogen source for nitrate biosynthesis in cellular and animal models.
Purpose of the Study:
- To investigate whether L-arginine serves as a precursor for endogenously synthesized nitrate in human subjects.
- To determine the in vivo incorporation of L-arginine nitrogen into urinary nitrate in humans.
Main Methods:
- Two human subjects received an oral dose of isotopically labeled [15N2]L-arginine.
- Urinary nitrate excretion was measured over a 24-hour period following the L-arginine dose.
Main Results:
- The subjects excreted 24 and 17 micromoles of [15N]nitrate per 24 hours, respectively.
- The presence of 15N in urinary nitrate confirmed the incorporation of L-arginine nitrogen.
Conclusions:
- L-arginine is a precursor for the endogenous synthesis of nitrate in humans.
- This finding extends the understanding of nitrate metabolism from in vitro and animal studies to human physiology.