NONAROMATIZING AND AROMATIZING 19-DEMETHYLASE PRODUCTS IN THE YOLK-SAC FLUID OF THE EARLY EQUINE CONCEPTUS
Bibliographic record
Abstract
Estrogens present in high concentrations in yolk-sac fluid of the early equine conceptus reflect high activity of cytochrome P450arom. Formation of C18 neutral steroids by P450arom has also been recorded for various equine and porcine tissues. In a previous study of steroids in extracts of yolk-sac fluid we detected large amounts of C19 androgens by radioimmunoassay (RIA), using an antiserum for androstenedione (A4). RIA after HPLC, however, revealed little or no A4. Instead, material coeluting with authentic norandrostenedione (19-norA) was detected by UV absorption and RIA, in which 19-norA showed high cross-reactivity (>100%). Subsequently, we have processed the ‘19-norA’ on a second HPLC system for better separation from testosterone. In addition, a solvolysis step before RIA, and followed by HPLC with RIA, showed that even greater quantities of 19-norA were present as a sulfoconjugate in yolk-sac fluid. This implies the occurrence of an enol isoform which is stabilized by conversion to the steroid sulfate. Confirmation of these unusual findings—nonaromatizing 19-demethylase activity and sulfoconjugation —was addressed, in part, by processing further samples (n=6) in a similar manner. Concentrations of 19-norA were about 13-fold greater in the sulfate than in the free fractions (mean values, 562 ± 165 and 41.3 ± 13.7 ng/ml, respectively). For comparison, amounts of estrone in these fractions were 36.0 ± 10.7 and 13.8 ± 2.6 ng/ml, as determined by a specific RIA. The total amounts of 19-norA were >10-fold higher than for estrone. Thus, the dominant activity for the P450arom in the equine conceptus at this stage of pregnancy seems to favor the formation of C18 neutral steroids. No rate of formation can be estimated from data such as these; but retention as a sulfoconjugate is clearly an outstanding feature. Its biological significance provides a subject for conjecture and a more general challenge in steroid metabolism. (poster)
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".