Thyroid hormone and reproduction: Regulation of estrogen receptors in goldfish gonads
Bibliographic record
Abstract
There is increasing evidence that thyroid hormones influence reproduction in vertebrates. However, little information is available on the mechanisms by which this happens. As a first step in determining these mechanisms, we test the hypothesis that the estrogen receptor subtypes (ERalpha, ERbeta-1, and ERbeta-2) are regulated by the thyroid hormone, (T(3)), in the gonads of goldfish. All three subtypes were down-regulated by T(3) in the testis or ovary. We also found evidence that T(3) decreased pituitary gonadotropin expression and decreased transcript for gonadal aromatase. Collectively, it appears that T(3) acts to diminish estrogen signaling by (1) decreasing pituitary LH expression and thus steroidogenesis, (2) down-regulating gonadal aromatase expression and thus decreasing estrogen synthesis from androgens, and (3) decreasing sensitivity to estrogen by down-regulating the ER subtypes. Goldfish are seasonal breeders, spawning once a year, and thus have two distinct periods of growth: somatic and reproductive. Circulating thyroid hormone levels have been found to increase just after spawning. Therefore, we propose that this may be an endocrine mechanism that goldfish use to switch their energy expenditure from reproductive to growth efforts in the goldfish.
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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) | 0.000 | 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) | 0.001 | 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".