IGF-1 Receptors in Xenopus laevis Ovarian Follicle Cells Support the Oocyte Maturation Response
Bibliographic record
Abstract
Insulin-like growth factor 1 (IGF-1)-stimulated amphibian oocyte maturation has been studied extensively by a number of laboratory groups, but in previous studies possible effects of IGF-1 on ovarian follicle cells had not been tested directly. In the study reported here, biochemical and immunofluorescent techniques were used to test Xenopus ovarian follicle cells for the presence of hormone-sensitive IGF-1 receptor. Anti-xIGF-1 receptor beta-subunit antibodies detected a 90- and 98-kDa protein doublet in manually dissected oocyte cortices (plasma membrane-vitelline envelope complexes) by protein immunoblotting both before and after removal of follicle cells from oocytes by sandpaper rolling. The 90-kDa IGF-1 receptor beta-subunit was also detected in follicle cell pellets. Tyrosine phosphorylation of the receptor beta-subunits was increased by treatment of cortices with 10 nM IGF-1 both in the presence and absence of associated follicle cells, was reduced by removal of follicle cells, and was detected in follicle cell pellets. Treatment of follicle cell pellets with nanomolar concentrations of IGF-1 stimulated receptor tyrosine phosphorylation in a dose-dependent fashion that correlated with dose-dependent stimulation of oocyte maturation. IGF-1 receptor was also detected in cultured follicle cells by immunofluorescence. Removal of follicle cells significantly reduced the IGF-1-stimulated oocyte maturation response. These results offer the first direct evidence for hormone-responsive IGF-1 receptors in Xenopus laevis ovarian follicle cells and demonstrate that follicle cells somehow support IGF-1-stimulated oocyte maturation.
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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 | 0.003 | 0.001 |
| 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) | 0.000 | 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".