HIGH ESTROGEN EXPOSURE IN VIVO REDUCES VOLUNTARY WHEEL RUNNING IN YOUNG AND OLDER FEMALE MICE
Bibliographic record
Abstract
Physiological levels of estrogen stimulate locomotor activity in running wheels by female rats and, spontaneous wheel running (WR) increases with age in female rodents. There is little information about the interactive effects of age and estrogen exposure on WR behaviors. We investigated WR behaviors of young and older female mice following in vivo exposure to different concentrations of estrogen (E: 17β-estradiol). Anestrus (basal serum E: 3 ± 1pg/ml) young (7–8 wk of age, n = 39) and older (50–52 wk of age, n = 39) female B6D2F1 mice were weighed, matched by weight and randomized, separately by age, to receive E pellets sc: high (H: 12μg/d), low (L: 3μg/d) and placebo (P). Females were housed individually, undisturbed, and without exposure to males, for a total of 28 days(d). One wk after pellet implantation, mice were given free access to in-cage running wheels (diameter: 22.8cm) linked to a computerized data collection system, with WR monitored during each 12h dark photoperiod for 21d. There were no significant differences in initial body weights, by E pellet group, although H and L mice were significantly heavier than P mice at study termination. There was a significant main effect of E but not age on cumulative WR volume during wk 1 ([E exposure: p < 0.001] mean ± SE H: 24.6 ± 1.6km, L: 33.2 ± 1.0km, P: 39.0 ± 1.5km). During wk 2, both age and E exposure were significant ([age p < 0.001] older: 44.3 ± 2.2km and young: 35.6 ± 2.4km and [E exposure p < 0.001] H: 28.9 ± 2.3km, L: 39.4 ± 2.1km, P: 51.6 ± 2.6km). WR was also higher in P mice during wk 3 (P>L = H)(p < 0.001) and older mice had marginally greater WR than young mice (p < 0.005). Final blood E levels differed across hormone exposure, but not age, groups (p < 0.001; H:323 ± 28pg/ml; L:40 ± 4pg/ml; P:8 ± 2pg/ml). The results demonstrate that high estrogen in vivo is associated with reduced spontaneous WR activity in mice and that the magnitude, but not direction, of this effect is influenced by age. Supported by NSERC of Canada.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".