Aromatase and Estrogen Receptor Expression in Early Equine Embryos.
Bibliographic record
Abstract
The early equine conceptus produces estrogens which are assumed to play a role in the interaction between the mare and the conceptus promoting the establishment and maintenance of pregnancy. It is well known that the extra-embryonic membranes such as the trophoblast synthesize estrogen by the presence of the enzyme aromatase (P450arom), which has also been detected in the hypoblast. Estrogen biosynthesis by the embryo proper has only recently been demonstrated in our investigations but the particular tissues involved remained unknown. To locate the site(s) of P450arom and estrogen receptors, immunohistochemical (IHC) staining was performed on paraffin embedded fixed sections of embryos proper at 24, 25, 26, and 27 (±1) days after conception. Trophoblast, endometrium and placenta were used as positive controls. P450arom was detected with mouse anti-human aromatase, specific for a single 55kDa band by immunoblot of horse trophoblast homogenate. Highest levels of P450arom were localized by IHC to trophoblast surface epithelium. Expression of P450arom in embryonic tissues was less pronounced but especially notable in the developing heart, mesonephros and the genital ridge. To locate embryonic tissues that might respond to estrogen, we surveyed the tissue distribution of estrogen receptors by IHC, using rabbit anti-mouse estrogen receptor (ER) alpha and mouse anti-human ER beta. With these antibodies, ER alpha and ER beta were detected in endometrial glands by IHC and as 55kDa and 59 kDA immunoreactive bands by immunoblots. Within the embryo proper both classes of estrogen receptors were located in many tissue types including developing heart, vascular endothelium, mesonephros, mesenchyme and genital ridge. In conclusion, this study reports the detection of P450arom at the earliest stage in development of an embryo proper for any mammalian species. It is suggested that the detection of aromatase and ERs may signify a direct role for estrogen biosynthesis in the equine embryo proper—perhaps related to differentiation and organogenesis. [Supported by NSERC, Equine Guelph, the Grayson-Jockey Club Research Foundation and OMAFRA.]
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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) | 0.003 | 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".