Comparative hepatic activity of xenobiotic-metabolizing enzymes and concentrations of organohalogens and their hydroxylated analogues in captive greenland sledge dogs (<i>Canis familiaris</i>)
Bibliographic record
Abstract
A captive study was performed with Greenland sledge dogs (Canis familiaris) fed a naturally organohalogen-contaminated diet (Greenland minke whale [Balaenoptera acutorostrata] blubber; exposed group) or a control diet (pork fat; control group). The catalytic activity of major xenobiotic-metabolizing phase I and II hepatic microsomal enzymes was assessed. Relative to control dogs, ethoxyresorufin-O-deethylase (EROD) activity in exposed dogs was twofold higher (p = 0.001). Testosterone hydroxylation yielded 6beta- and 16beta-hydroxy (OH) testosterone and androstenedione, with higher rates of production (23-27%; p < or = 0.03) in the exposed individuals. In the exposed dogs, epoxide hydrolase (EH) activity was 31% higher (p = 0.02) relative to the control dogs, whereas uridine diphosphoglucuronosyl transferase (UDPGT) activity was not different (p = 0.62). When the exposed and control dogs were combined, the summed (sigma) plasma concentrations of OH-polychlorinated biphenyl (PCB) congeners were predicted by plasma sigmaPCB concentrations and EROD activity (p < or = 0.04), whereas testosterone hydroxylase, EH, and UDPGT activities were not significant predictors of these concentrations. Consistent results were found for individual OH-PCB congeners and their theoretical precursor PCBs (e.g., 4-OH-CB-187 and CB-183, and 4-OH-CB-146 and CB-146) and for EROD activity. No association was found between sigmaOH-polybrominated diphenyl ether (PBDE) and sigmaPBDE plasma concentrations, or between potential precursor-metabolite pairs, and the enzyme activities. The present results suggest that liver microsomal EROD activity and plasma PCB concentrations have a greater (e.g., relative to EH activity) predictive power for the occurrence of plasma OH-PCB residues in sledge dogs. These results also suggest that plasma OH-PBDEs likely are not products of cytochrome P450-mediated transformation but, rather, are accumulated via the diet.
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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 | 0.001 | 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 | 0.000 |
| 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".