Relationship between Pineal N-Acetyltransferase Activity, Pineal Melatonin and Serum Melatonin in Rats under Different Lighting Conditions
Bibliographic record
Abstract
Pineal N-acetyltransferase (NATase) activity has often been used as an indicator of pineal melatonin (MT) production, and the rhythms of pineal and serum MT levels are assumed to be parallel. However, these issues require further examination in view of some recent findings. In the present study, the 24-hour rhythms of pineal NATase, pineal MT content and serum MT concentrations were examined in groups of rats exposed to four artificial lighting regimens: (a) 16 h of light, 8 h of darkness (LD 16:8) for 2 weeks; (b) LD 12:12 for 2 weeks; (c) LD 4:20 for 2 weeks, and (d) LD 4:20 for 4 weeks. Under the above lighting conditions, the rhythms of pineal NATase, serum and pineal MT contents when tested demonstrated a closely parallel relationship. These results supported the idea that pineal NATase accurately reflected MT synthesis and that the rhythms of pineal and serum MT content were in phase under long and short photoperiods, in spite of extrapineal sites of MT synthesis. Further, the results also demonstrated that the timing of the MT peaks in the serum and the pineal may depend on the length of the adaptation period to the environmental lighting. When the rats were housed under a short photoperiod (LD 4:20), the peak MT levels appeared in the middle of the dark period after 2 weeks but shifted towards the end of the dark period after 4 weeks.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".