Dietary proline and glutamine contribute to arginine and citrulline synthesis in healthy adult men
Bibliographic record
Abstract
We have previously shown in human neonates and piglets that proline is the sole dietary precursor for arginine synthesis. It is unclear in adult humans whether proline is a dietary precursor for arginine. We performed a multitracer isotope study using 15 N 2 ‐ureido arginine, 15 N proline and 1‐ 13 C glutamine to further elucidate synthesis of citrulline and arginine. Primed, and intermittent infusion of labeled 15 N proline and 1‐ 13 C glutamine were given enterally to 5 healthy men fed a standardized milkshake diet. Blood was sampled at plateau enrichment between 1.5 and 3 hours. Plasma enrichment was seen for all tracers giving flux estimates of 93 μmol/kg/hr for arginine, 154 μmol/kg/hr for proline and 770 μmol/kg/hr for glutamine. Transfer of the label from proline and glutamine to arginine and the intermediaries, ornithine and citrulline, was seen in all subjects. The estimated rate of synthesis of arginine from proline was 3.7 μmol/kg/hr and from glutamine was 8.5 μmol/kg/hr. We have shown that in healthy adult humans, both proline and glutamine contribute significantly in providing the carbon chain for arginine synthesis.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".