Direct Free Fatty Acid Uptake Into Human Adipocytes In Vivo
Bibliographic record
Abstract
We sought to assess whether direct uptake of circulating free fatty acids (FFAs) by adipocytes occurs in vivo in overnight postabsorptive humans and, if so, whether there are regional differences in uptake between lean and obese women and men. We used bolus injections of radiolabeled FFA tracers followed by carefully timed adipose tissue biopsies. First, we validated a method to measure direct adipocyte FFA uptake and then quantitated this process using the modified methods in normal-weight postabsorptive men and women. We then used a continuous infusion of radiolabeled FFA to measure direct and indirect (VLDL) regional adipose tissue uptake in obese men and women. Direct FFA uptake was greater in women than men: 8.2 +/- 0.6 vs. 4.0 +/- 0.5% (P < 0.0001) of FFAs were taken up by subcutaneous adipose tissue, respectively. Abdominal subcutaneous fat took up FFAs more avidly than femoral fat in men, but this did not occur in women. Similar sex and regional difference were found to occur in obese women and men. Gene expression of fatty acid transporters was greater in abdominal than femoral fat in men (P < 0.05) but not in women (P = 0.80). We observed sex- and site-specific recycling of circulating FFAs into subcutaneous fat. This is a novel FFA disposal pathway that may also play a role in the development or maintenance of body fat distribution. Regional variations in facilitated fatty acid transport may contribute to this process.
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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) | 0.000 | 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".