Estetrol does not bind sex hormone binding globulin or increase its production by human HepG2 cells
Bibliographic record
Abstract
OBJECTIVES: To determine whether human sex hormone binding globulin (SHBG) binds estetrol (E4), and to assess whether E4 stimulates the production of SHBG by human hepatocytes. METHODS: Competitive ligand binding assays have been used to assess the relative binding affinity of E4 to human SHBG using either [3H]5alpha-dihydrotestosterone or [3H]estradiol as labeled ligands. The effect of E4 on the production of SHBG has been assessed by a fluoroimmunometric assay in wild-type human HepG2 cells and in human Hep89 cells that over-express the human estrogen receptor (ER) alpha, and compared to the effect of ethinylestradiol, estradiol and estriol. RESULTS: There was no detectable binding of E4 to the human SHBG steroid-binding sites. By contrast, testosterone and estradiol were bound with high affinity and the synthetic estrogen ethinylestradiol was found to bind SHBG with low affinity. Estetrol does not stimulate ERalpha-mediated increases in SHBG production by HepG2 or Hep89 cells, in contrast to ethinylestradiol, estradiol and estriol. CONCLUSIONS: These data indicate that SHBG has no influence on the plasma distribution of E4 or its availability to target tissues. In addition, it is shown that E4 has no effect on SHBG production by human hepatocytes.
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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) | 0.005 | 0.002 |
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".