Rat duodenal IRP1 activity and iron absorption in iron deficiency and after H<sub>2</sub>O<sub>2</sub> perfusion
Bibliographic record
Abstract
BACKGROUND: Iron regulatory protein 1 (IRP1), a post-transcriptional regulator of iron metabolism, is activated in the duodenum of iron-deficient animals, which is associated with increased iron absorption. In cell cultures IRP1 was also activated by iron-independent signals, such as H(2)O(2). Here we investigate whether luminal perfusion of rat duodenum with H(2)O(2) activates duodenal IRP1 and modulates duodenal iron absorption. METHODS: Duodena from iron-adequate Sprague-Dawley rats were luminally perfused with H(2)O(2). Iron regulatory protein-1 activity was determined in duodenal mucosa or in villus and crypt preparations by an electrophoretic mobility shift assay. Duodenal (59)Fe absorption was measured in isolated, perfused duodenal segments ex vivo and in ligated loops in vivo. (59)Fe uptake from the blood side was assessed after i.v. injection of (59)Fe-nitrilotriacetic acid. RESULTS: Similar to iron deficiency, the perfusion with 0-50 mM of H(2)O(2) increases duodenal IRP1 activity along the entire crypt villus-axis in a dose-dependent manner. After H(2)O(2) treatment, IRP1 remains activated for 12-24 h in the tips and for 72 h in the crypts. In iron-deficiency, IRP activation correlates with increased (59)Fe absorption. However, the H(2)O(2) treatment fails to stimulate any increase in (59)Fe uptake, without promoting damage of mucosal architecture or impairing glucose and water transport. CONCLUSION: Duodenal (59)Fe uptake is not affected by the H(2)O(2)-mediated activation of IRP1.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".