Fasting Insulin Levels Influence Plasma Leptin Levels Independently from the Contribution of Adiposity: Evidence from Both a Cross-Sectional and an Intervention Study<sup>1</sup>
Bibliographic record
Abstract
The aim of the present investigation was to determine whether leptinemia is only a reflection of the status of fat stores or if insulinemia has a significant influence over leptin levels. Study 1 focused on the association between fasting plasma insulin and leptin in subjects of the Quebec Family Study who were first classified as either high- or low-insulin individuals and were then individually matched on the basis of fat mass (FM). In Study 2, 19 men and 23 women took part in a 15-week weight loss program that consisted of drug therapy (fenfluramine, 60 mg/day) or placebo coupled to an energy-restricted diet (-2930 kJ/day). Body weight, FM, and fat-free mass (assessed by underwater weighing) as well as visceral and sc abdominal and mid-thigh adipose tissue measured by computed tomography were assessed before and after weight loss. Blood samples were drawn and analyzed for fasting plasma insulin and leptin before and after weight loss. In Study 1, significant positive associations were noted between log10 transformed fasting insulin and leptin in both men (r = 0.55, P < 0.0001) and women (r = 0.48, P < 0.0001). Moreover, after having carefully matched high-insulin to low-insulin individuals on the basis of FM, significantly lower leptin levels were observed in the low-insulin groups, in men (5.5 vs. 8.1 ng/mL, P < 0.05) as well as in women (18.7 vs. 24 ng/mL, P < 0.05). Results from Study 2 showed significant reductions of body weight, FM, fat-free mass, visceral abdominal tissue, sc abdominal tissue, and mid-thigh adipose tissue levels in men and women in response to the weight loss protocol. Moreover, the decrease in fasting plasma insulin was the only significant correlate of changes in fasting plasma leptin levels during weight loss, even after corrections for changes in FM in both men (r = 0.50, P < 0.05) and women (r = 0.46, P < 0.05). These results suggest that in a population characterized by a wide range of adiposity hyperinsulinemia has the potential to modulate leptin levels beyond what can be explained by total adiposity. Moreover, this relation also seems to exist in a dynamic setting (i.e. during weight loss) because changes in insulin were independent predictors of the changes in leptinemia in both men and women after correction for changes in FM.
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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 | 0.004 | 0.006 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".