Determination of the estrogenic and antiestrogenic effects of environmental contaminants in chicken embryo hepatocyte cultures by quantitative-polymerase chain reaction
Bibliographic record
Abstract
A method was developed to measure the estrogenic and antiestrogenic effects of various chemicals and organochlorine extracts in chicken embryo primary hepatocyte cultures. Messenger RNAs (mRNAs) for the estrogen-inducible egg yolk proteins, vitellogenin II (VTGII), and very low-density lipoprotein apoprotein II (apoII), were measured by multiplex quantitative reverse transcription-polymerase chain reaction (Q-PCR). After 48 h of exposure, both VTGII and apoII mRNA levels were induced by moxestrol (1-1,000 nM), 17 beta-estradiol (10-1,000 nM), o,p'-DDT (apoII: 1,000 and 10,000 nM, VTGII: 10,000 nM), 4-tertoctylphenol ([OP]; apoII: 20 and 50 microM, VTGII: 10-50 microM), and methoxychlor ([MXCL]; apoII: 5-50 microM, VTGII: 20 and 50 microM). Tamoxifen (100 and 1,000 nM) induced apoII mRNA only, and bisphenol A (BPA) was not estrogenic. Inhibition of moxestrol-mediated VTGII or apoII mRNA induction by MXCL, o,p'-DDT and tamoxifen indicated that these chemicals were also antiestrogenic at concentrations similar to those which caused estrogenic responses. Organochlorine extracts prepared from herring gull embryo yolk sacs obtained from three Great Lakes sites and one Atlantic coast site (reference site) did not show any estrogenic activities. However, the same extracts from all three Great Lakes sites had antiestrogenic activities. These results indicate that wild birds may be susceptible to the estrogenic or antiestrogenic effects of environmental contaminants.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".