Characterization of Nuclear and Membrane Progesterone Receptors in Bovine Endometrium.
Bibliographic record
Abstract
Progesterone (P4) is essential for maintenance of pregnancy and also plays an important role in the timing of luteolysis in ruminants. The time from estrus to luteolysis is regulated by P4 since a) treatment of cows with P4 early in the estrous cycle results in premature luteolysis and b) delaying the action of P4 on the endometrium by the use of an antagonist delays luteolysis. However, the exact mechanism(s) of action of P4 in the endometrium is still not known. Nuclear progesterone receptors (nPR) occur naturally in A and B forms, which result from alternative promoter usage of the same gene. The two PR forms are hormonally and developmentally regulated. The specific role for each of these two PR subtypes in the regulation of endometrial function is unclear. However, the existence of elaborate mechanisms regulating their production suggests that the relative levels of PRA and PRB in cells is critical for appropriate cellular response to P4; for example in human parturition when there is no change in plasma P4 concentrations. P4 can also have non-genomic effects and membrane receptors (mPR) in the epithelial cells of the ruminant endometrium have been shown in sheep and cows, but no detailed studies have been performed. The hypothesis for this study is that changes in mPR and/or the ratio of PRA/PRB during the estrous cycle in the cow are responsible for regulating endometrial function, including induction of luteolysis. The objectives of this present study are to determine if changes in PRA, PRB and mPR occur during the estrous cycle. Endometrial samples, from uterine horns ipsi- and contra-lateral to the corpus luteum, were collected during the early, mid and late stages of the estrous cycle from cows (4 cows per stage) at the slaughterhouse and snap-frozen until analysis. Measurement of mRNA for PRA and PRB by RT-PCR has been established and the results show that both isoforms are expressed at all stages of the cycle. Quantitative PCR has now to be performed to determine if changes occur during the cycle. Protein expression (measured by Western blotting) shows PRB and PRA at all stages of the cycle. There was a higher expression of PRA in the ipsi-lateral horn (P=0.05, n=4) but no difference was observed at the different stages of the cycle in either horn. Further studies are in progress to determine if changes occur in the different cell types of the endometrium. Preliminary data show that mPR? mRNA is present in the endometrium throughout the estrous cycle. These data show that mPR and the different isoforms of the nPR are present in the bovine endometrium and could play an important role in its regulation. This work was supported by NSERC.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.002 | 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".