Endogenous Melanocortin Antagonist in Fish: Structure, Brain Mapping, and Regulation by Fasting of the Goldfish Agouti-Related Protein Gene
Bibliographic record
Abstract
Agouti-related protein (AGRP) is a naturally occurring antagonist of melanocortin. In mammals, central AGRP expression is restricted to the arcuate nucleus in which it plays a key role in the control of energy balance by antagonizing melanocortin effects at melanocortin 4 receptors. In goldfish, melanocortin 4 receptor is profusely expressed within the main brain areas for the control of energy balance, and central administration of agonist or antagonist analogs inhibits or stimulates food intake, respectively. Here we demonstrate that the goldfish genome has a homologous gene to mammalian AGRP. Detailed brain mapping by in situ hybridization shows that AGRP is exclusively expressed in the ventrobasal hypothalamic lateral tuberal nucleus, the teleostean homolog of the arcuate nucleus. Fasting up-regulates its mRNA levels in the lateral tuberal nucleus. In the periphery, AGRP is expressed in several tissues including ovary, muscle, and ventral skin, suggesting that AGRP might regulate peripheral actions of melanocortin peptides. The results provide the first evidence for an endogenous melanocortin antagonist in nontetrapod species and suggest that hypothalamic overexpression during fasting might regulate the inhibitory effects of melanocortin peptides on food intake in goldfish.
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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 | 0.000 | 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) | 0.001 | 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".