Role of Angiotensin II in the Periovulatory Epidermal Growth Factor-Like Cascade in Bovine Granulosa Cells In Vitro1
Bibliographic record
Abstract
Angiotensin II (AGT-2) induces follicular prostaglandin release in a number of species and ovulation in rabbits. Conversely, AGT-2 antagonists block ovulation in cattle. To determine the mechanism of action of AGT-2, we used a bovine granulosa cell model in which luteinizing hormone (LH) increased the expression of genes essential for ovulation in a time- and dose-dependent manner. The addition of AGT-2 to LH-stimulated cells significantly increased abundance of prostaglandin-endoperoxide synthase 2 (PTGS2) mRNA and protein, whereas AGT-2 alone had no effect. Upstream of PTGS2, AGT-2 increased abundance of mRNA encoding the epidermal growth factor-like ligands amphiregulin (AREG) and epiregulin (EREG) at 6 h posttreatment and abundance of a disintegrin and metalloprotease 17 (ADAM17), a sheddase, within 3 h of treatment. Inhibiting sheddase activity abolished the stimulatory effect of AGT-2 on AREG, EREG, and PTGS2 mRNA. The addition of selective AGT-2 antagonists to cells stimulated with LH plus AGT-2 demonstrated that AGT-2 did not act through the type 1 receptor and did not increase mitogen-activated protein kinase 3/1 phosphorylation. Combined with previous data from studies in vitro, we conclude that AGT-2 is an essential cofactor for LH in the early increase of ADAM expression/activity that induces the cascade of events leading to ovulation.
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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".