Melatonin Receptor Activation Regulates GnRH Gene Expression and Secretion in GT1–7 GnRH Neurons
Bibliographic record
Abstract
Melatonin plays a significant role in the control of the hypothalamic-pituitary-gonadal axis. Using the GT1-7 cell line, an in vitro model of GnRH-secreting neurons of the hypothalamus, we examined the potential signal transduction pathways activated by melatonin directly at the level of the GT1-7 neuron. We found that melatonin inhibits forskolin-stimulated adenosine 3'-, 5'-cyclic monophosphate accumulation in GT1-7 cells through an inhibitory G protein. Melatonin induced protein kinase C activity by 1.65-fold over basal levels, increased the phosphorylation of extracellular signal-regulated kinase 1 and 2 proteins, and activated c-fos and junB mRNA expression in GT1-7 cells. Using the protein kinase A inhibitor H-89, the protein kinase C inhibitor bisindolylmaleimide, and the mitogen-activated protein kinase kinase inhibitor PD98059, we found that the melatonin-mediated cyclical regulation of GnRH mRNA expression may involve the protein kinase C and the extracellular signal-regulated kinase 1 and 2 pathways, but not the protein kinase A pathway. We found that melatonin suppresses GnRH secretion by approximately 45% in the GT1-7 neurons. However, in the presence of the inhibitors H-89, bisindolylmaleimide, and PD98059 melatonin was unable to suppress GnRH secretion. These results provide insights into the potential signal transduction mechanisms involved in the control of GnRH gene expression and secretion by melatonin.
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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 | 0.001 |
| 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".