Glucagon-Like Peptide-1 Receptor Activation Antagonizes Voltage-Dependent Repolarizing K+ Currents in β-Cells
Bibliographic record
Abstract
Glucagon-like peptide-1 (GLP-1) acts through its G-protein-coupled receptor to enhance glucose-stimulated insulin secretion from pancreatic beta-cells. This is believed to result from modulation of at least two ion channels: ATP-sensitive K(+) (K(ATP)) channels and voltage-dependent Ca(2+) channels. Here, we report that GLP-1 receptor signaling also regulates the activity of beta-cell voltage-dependent K(+) (K(V)) channels, themselves potent glucose-dependent regulators of insulin secretion. GLP-1 receptor activation with exendin 4 (10(-8) mol/l) in rat beta-cells antagonized K(V) currents by 43.3 +/- 6.3%, whereas the GLP-1 receptor antagonist exendin 9-39 had no effect. The effect of GLP-1 receptor activation on K(V) currents could be replicated (current reduction of 55.7 +/- 6.0%) by G-protein activation with GMP-PNP (10 nmol/l). The cAMP pathway antagonist Rp-cAMPS (100 micro mol/l) prevented current inhibition by exendin 4, implicating cAMP signaling in GLP-1 receptor modulation of beta-cell K(V) currents. Finally, exendin 4 (10(-8) mol/l) increased the amplitude (130 +/- 5.7%) and duration (285 +/- 15.9%) of the beta-cell depolarization response to current injection, independent of any effect on K(ATP) or Ca(2+) channels. The present results demonstrate that GLP-1 receptor signaling can antagonize beta-cell repolarization by reducing voltage-dependent K(+) currents, an effect likely to contribute to GLP-1's glucose-dependent insulinotropic effect.
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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) | 0.000 | 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 | 0.001 |
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 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".