Insulin stimulates glucose metabolism via the pentose phosphate pathway in <i>Drosophila</i> Kc cells
Bibliographic record
Abstract
Drosophila melanogaster has become a prominent and convenient model for analysis of insulin action. However, to date very little is known regarding the effect of insulin on glucose uptake and metabolism in Drosophila. Here we show that, in contrast to effects seen in mammals, insulin did not alter [(3)H]2-deoxyglucose uptake and in fact decreased glycogen synthesis ( approximately 30%) in embryonic Drosophila Kc cells. Insulin significantly increased ( approximately 1.5-fold) the production of (14)CO(2) from D-[1-(14)C]glucose while the production of (14)CO(2) from D-[6-(14)C]glucose was not altered. Thus, insulin-stimulated glucose oxidation did not occur via increasing Krebs cycle activity but rather by stimulating the pentose phosphate pathway. Indeed, inhibition of the oxidative pentose phosphate pathway by 6-aminonicotinamide abolished the effect of insulin on (14)CO(2) from D-[U-(14)C]glucose. A corresponding increase in lactate production but no change in incorporation of D-[U-(14)C]glucose into total lipids was observed in response to insulin. Glucose metabolism via the pentose phosphate pathway may provide an important source of 5'-phosphate for DNA synthesis and cell replication. This novel observation correlates well with the fact that control of growth and development is the major role of insulin-like peptides in Drosophila. Thus, although intracellular signaling is well conserved, the metabolic effects of insulin are dramatically different between Drosophila and mammals.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".