Tryptophan restriction partially recapitulates the age-dependent effects of total amino acid restriction on energy balance in diet-induced obese rats.
Bibliographic record
Abstract
Moderate dietary protein restriction promotes hyperphagia and thermogenesis; however, little is known of whether these responses are due to restriction of the essential amino acids tryptophan and histidine. Here, we determined whether restriction of tryptophan and histidine alone recapitulate the effects of total amino acid restriction on energy balance, and whether the metabolic responses are age-dependent. We fed young (12 weeks old) and older (29 weeks old) diet-induced obese rats with one of four high-fat diets: control (CON, 100% amino acid requirement), total amino acid restriction (TAA, 67% amino acid restriction), tryptophan restriction (TRP, 67% tryptophan restriction) or histidine restriction (HIS, 67% histidine restriction) for 21 days. Energy balance, hormones, and key markers of hepatic nutrient sensing and brown adipose thermogenesis were measured. We found that TAA increased food intake in both young and older rats, with TRP, but not HIS, transiently simulating the hyperphagia. TAA promoted sympathetically mediated increase in energy expenditure in young rats partly through increased β2-adrenergic and FGF21 signaling in brown fat; TRP partially emulated these responses. TRP and HIS transiently increased fat mass in young rats, and TAA promoted adiposity in older rats. TAA, TRP and HIS increased postprandial FGF21 concentrations in older rats. TAA induced age-dependent differential changes in markers of hepatic amino acid sensing; TRP and HIS partially mimicked these responses. Collectively, restriction of tryptophan, but not histidine, partially recapitulated the age-dependent metabolic effects of total amino acid restriction, in concert with distinct changes in hepatic amino acid sensing and signaling mechanisms.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".