URINARY EXCRETION KINETICS OF 1-HYDROXYPYRENE IN RATS SUBCHRONICALLY EXPOSED TO PYRENE OR POLYCYCLIC AROMATIC HYDROCARBON MIXTURES
Bibliographic record
Abstract
The urinary excretion kinetics of 1-hydroxypyrene (1-OHP) were studied in male Sprague-Dawley rats exposed orally, on Tuesdays and Fridays for 10 consecutive weeks, to 0.046 mg/kg/d of pyrene or 0.3, 1 or 3 mg/kg/d of polycyclic aromatic hydrocarbon (PAH) mixtures containing pyrene (0.046, 0.15, and 0.46 mg/kg/d, respectively). During the subchronic exposure, 24-h urine samples were collected on Mondays (prior to exposure) and Tuesdays (after exposure) for all exposure groups. During a 14-d period following last exposure in rats treated with 3 mg/kg/d of PAH mixture, 24-h urine samples were collected at frequent time intervals (0-24, 48-72, 96-120, 144-168, 193-217, 313-338 h). Whatever the administered dose, repeated exposures to pyrene and PAH mixtures resulted in a progressive time-dependent increase in the daily urinary excretion of 1-OHP. After 10 wk of treatment, daily excretion rates were on average 5 times higher than those observed after the first administration. Following the subchronic exposure to 3 mg/kg/d of PAH mixture, the time profile of 1-OHP excretion in rat urine showed a multiphasic elimination. An average first-order apparent elimination half-life of 26.5 h could be estimated for the 48-168 h period following the end of the exposure. The observed time-dependent increase in 1-OHP excretion values upon repeated exposures to PAHs does not appear to result from a PAH enzyme induction effect of pyrene metabolism to 1-OHP. Rather, the slow release of residual pyrene accumulated in a long-term compartment and/or the enterohepatic recirculation of 1-OHP and other pyrene metabolites may play significant roles in the observed urinary excretion kinetics of 1-OHP. Furthermore, the absence of mixture effect on the urinary excretion of 1-OHP suggests that 1-OHP is a good bioindicator of exposure to complex PAH mixtures, in the dose range used in this study.
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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 | 0.000 | 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 | 0.000 |
| 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".