OR23-4 Low-Dose Gestational BPA Exposure Alters Circadian Rhythms in Mice
Bibliographic record
Abstract
Bisphenol A (BPA) is a well-characterized endocrine disruptor known to act via multiple steroid signaling pathways. Previously we have shown that the hypothalamus, a key regulator of neuroendocrine activity, is particularly susceptible to endocrine disruption by BPA, with low-dose gestational exposure resulting in accelerated neurogenesis and altered behavior, including hyperactivity, in both zebrafish and mice. The suprachiasmatic nucleus (SCN) of the hypothalamus is the regulator of the circadian clock, and we hypothesize a link between altered SCN function and the observed hyperactivity in BPA exposed animals. Here we present the effects of low-dose, environmentally relevant gestational BPA exposure on circadian rhythms in mice. We characterized mice exposed to BPA (50 μg/kg via diet) in utero by measuring their activity levels during a normal 12:12 light/dark (l/d) cycle, followed by entrainment to a 24h dark (d/d) period. We observed significant alterations in circadian rhythms as a result of gestational BPA exposure. BPA mice were significantly more active than control mice in l/d conditions, specifically in the late stages of the dark phase when control mice had usually completed their daily bouts of activity. BPA-exposed mice also exhibited less of an anticipatory onset of activity just prior to the start of the dark phase, and we observed a slight, female-specific increase in circadian period (tau). BPA-mediated disruptions of circadian rhythms were exaggerated under d/d conditions. BPA mice again showed significantly higher activity than control mice, and both male and female mice exhibited a significant decrease in tau. Finally, we observed that BPA-exposed mice appear to entrain more quickly to new conditions, both in the shift from l/d to d/d, and in response to short-term light exposure during the d/d testing. Overall, we conclude that low-dose gestational BPA exposure alters circadian rhythms under various conditions, the first such finding in a mammalian model in vivo, and that this may be a contributing factor to the observed hyperactivity in BPA-exposed mice.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.003 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
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".