Estrogens dynamically regulate neurogenesis in the dentate gyrus of adult female rats
Bibliographic record
Abstract
Abstract Estrone and estradiol differentially modulate neuroplasticity and cognition, but how they influence maturation pathways of new neurons in the adult hippocampus is not known. The present study assessed the effects of estrone and estradiol on various aspects of neurogenesis in the dentate gyrus (DG) of ovariectomized young adult Sprague-Dawley rats using daily subcutaneous injections of 17β-estradiol or estrone. Rats were injected with a DNA synthesis marker, 5-bromo-2-deoxyuridine (BrdU), and were perfused one, two, or three weeks after BrdU injection and treatment. Immunofluorescent labelling for GFAP/Sox2 was used to examine the density of neural stem/progenitor cells and Ki67 for cell proliferation. Double-immunofluorescent labelling of BrdU with doublecortin (DCX) or NeuN was used to examine the attrition and maturation of adult-born neurons over time. Length of time post ovariectomy was associated with a reduction in neural stem/progenitor cells in the DG. Estrogens had effects on different components of neurogenesis after one week of exposure but not after prolonged treatment. Estradiol enhanced, whereas estrone reduced, cell proliferation after one week but not after longer exposure to hormones. Both estrogens increased the density of BrdU/DCX-ir cells after one week of exposure but showed greater attrition of new neurons between one and two weeks after exposure, suggesting that the effects of estrogens on neurogenesis were not sustained. These results demonstrate that estrogens modulate several aspects of adult hippocampal neurogenesis differently in the short term, but may lose their ability to influence neurogenesis after long-term exposure.
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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 | 0.000 |
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 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".