Transforming growth factor-beta1 inhibits steroidogenesis in human trophoblast cells
Bibliographic record
Abstract
Transforming growth factor-beta (TGF-beta) is an important regulator of placental development and function. In this study, we have investigated the effect of TGF-beta1 on steroidogenesis, as well as its sites of action in the steroidogenic pathway by using a choriocarcinoma cell line, JEG-3, and a normal trophoblast cell line (NPC). The effect of TGF-beta1 on progesterone and estradiol production was evaluated in the absence or presence of a membrane-permeable analogue of cholesterol and some intermediate substrates of steroidogenic enzymes. The effect of TGF-beta1 on P450 aromatase (P450arom) mRNA levels was determined by Northern blot analysis. TGF-beta1 significantly decreased progesterone production in both NPC and JEG-3 cells. The inhibitory effect of TGF-beta1 on progesterone production was reversed by addition of 22R-hydroxycholesterol, a membrane-permeable analogue of cholesterol, or pregnenolone. In JEG-3 cells, TGF-beta1 also inhibited estradiol production when androstenedione, but not estrone, was added to the culture. Estradiol production was too low to be detected in NPC cells. Treatment with TGF-beta1 also suppressed aromatase mRNA levels. This study has demonstrated that TGF-beta1 inhibits progesterone and estradiol production by trophoblast cells, and that the sites of TGF-beta1 action on progesterone and estradiol production are likely to be cholesterol transport and P450arom respectively.
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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 | 0.001 |
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".