Anaplerosis of the citric acid cycle: role in energy metabolism of heart and skeletal muscle
Bibliographic record
Abstract
Efficient energy transfer in heart and skeletal muscle requires a series of moiety-conserved cycles. The intermediaries of the metabolic cycles are finely regulated to maintain a dynamic state of equilibrium. In heart muscle, depletion of the citric acid cycle (TCA cycle) through a block of 2-oxoglutarate dehydrogenase results in a rapid decline of contractile function, which is reversed by the addition of substrates promoting flux through the carboxylating enzymes, malic enzyme, pyruvate carboxylase and propionyl-CoA carboxylase. Anaplerosis describes a pathway, which replenishes a metabolic cycle. We show that enzymes for anaplerosis of the TCA cycle are expressed in heart and skeletal muscles. The role of anaplerosis of the TCA cycle in skeletal muscle is not entirely clear, but there is substantial evidence for its operational control during exercise. While the anaplerotic flux of carbon into the TCA cycle exceeds the removal of cycle intermediates, this process is only transient and reverses with prolonged exercise. It remains to be determined, however, whether the initial increase in TCA cycle intermediates is obligatory in order to attain high rates of TCA cycle flux, or primarily reflects a mass action phenomenon owing to increased substrate availability for anaplerotic pathways.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.004 |
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 source (direct Gemma or distilled Codex), 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".