Arginine, ornithine, and proline interconversion is dependent on small intestinal metabolism in neonatal pigs
Bibliographic record
Abstract
We have previously shown that arginine deficiency is exacerbated by the removal of dietary proline in orally, but not parenterally, fed piglets. Therefore, we hypothesized that the net interconversions of proline, ornithine, and arginine primarily occur in the small intestine of neonatal piglets. Ten intragastrically fed piglets received either intraportal (IP) or intragastric (IG) primed, constant infusions of [guanido-(14)C]arginine and [U-(14)C]ornithine + [2,3-(3)H]proline. By infusing amino acid isotopes via the stomach compared with the portal vein, we isolated small intestinal first-pass metabolism in vivo. During IP infusion, fractional net conversions (%) from proline to ornithine (0), ornithine to arginine (11 +/- 6), and ornithine to proline (5 +/- 1) were lower (P < 0.05) than during IG infusion (39 +/- 8, 18 +/- 6, and 42 +/- 12, respectively); we speculate that these data are due to the localization of ornithine aminotransferase to the gut. The balance of these conversions indicated a large synthesis of arginine (70.0 micromol. kg(-1). h(-1)) by the gut, with a corresponding degradation of ornithine (70.8 micromol. kg(-1). h(-1)) and no change in proline balance. Gut synthesis of arginine from proline (48.1 micromol. kg(-1). h(-1)) was 50% of its requirement, whereas proline synthesis from arginine (33.0 micromol. kg(-1). h(-1)) amounted to 10% of its requirement. Overall, arginine synthesis is more dependent on the gut than proline synthesis. In situations in which gut metabolism is compromised, such as during parenteral nutrition or gastrointestinal disease, arginine and proline are individually indispensable because their biosyntheses are negligible.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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 | 0.001 |
| 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".