To be or not to be: Regulation of the Intrinsic Activity of GLUT4
Bibliographic record
Abstract
Insulin increases the rate of glucose uptake into muscle and fat cells. Numerous studies provide evidence that this is accomplished through an increase in the cell-surface amount of the facilitative glucose transporter GLUT4. Diverse techniques have been used to document a time-dependent gain in surface GLUT4, often in conjunction with a decrease in its intracellular content. These include subcellular fractionation coupled to immunoblotting, affinity photolabelling coupled to immunoprecipitation, and surface detection by immunofluorescence and immunoelectron microscopy. However, there are also abundant reports of a discrepancy between the extent of stimulation of the rate of glucose uptake by insulin and the increase in the amount of cell-surface transporters. One interpretation of this discrepancy is that insulin regulates the intrinsic activity of GLUT4 in addition to recruiting transporters to the cell surface. Several interpretations of this discrepancy can be offered, based on the experimental techniques used to measure glucose uptake and cell-surface GLUT4. Here we discuss the methods used to quantify these observations. Subsequently, we inspect the studies that have measured the insulin-stimulated increase in cell-surface GLUT4 concurrently with glucose uptake, in order to determine if there is realistic evidence to support the hypothesis that insulin regulates GLUT4 intrinsic activity. We conclude that in spite of various possible explanations for the discrepancy between the stimulation of glucose uptake and that of cell surface GLUT4, there is solid evidence to suggest that insulin increases the intrinsic activity of GLUT4. Keywords: insulin, glucose transporters (gluts), expression, translocation, plasma membrane (pm)
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".