Metabolism and Cytotoxic Mechanisms of Nitroglycerin in Isolated Rat Hepatocytes
Bibliographic record
Abstract
It has been proposed that organic nitrates such as glyceryl trinitrate (GTN), used in the treatment of cardiovascular diseases, act by producing nitric oxide (NO). However, the biochemical pathway for NO formation from GTN is not well understood. In the present study, we showed that nitrate formation from GTN, by isolated rat hepatocytes, was inhibited about 50% when cellular glutathione was depleted and about 40% when cytochrome P-450 was inactivated by SKF525A. This suggests that GTN is metabolized and/or NO is formed by three pathways in rat hepatocytes: 1) denitrification of GTN by GSH/GSH transferase system; 2) reduction of GTN by reduced cytochrome P-450; and 3) GTN can directly react with protein thiol groups of cellular macromolecules (transnitrosation). At much higher concentrations, GTN was toxic towards hepatocytes (LC 50= 2 mM for 2 h of incubation) and cytotoxicity was accompanied by GSH and ATP depletion. Depleting GSH and/or inactivating cytochrome P-450 beforehand markedly increased GTN cytotoxicity. The permeable thiol reductant dithioteritol unlike antioxidants was found to be an effective antidote, even if added to the cells an hour after GTN. The results suggest that GTN-induced cytotoxicity is mediated by transnitrosyllation of mitochondrial, structural and vital protein thiols.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".