Biological and Radioimmunological Evidence for Melanocyte Stimulating Hormones (MSH) of Extrapituitary Origin in the Rat Brain
Bibliographic record
Abstract
The possible existence of extrapituitary melanocyte stimulating hormone (MSH) in various regions of the rat brain has been studied in intact and hypophysectomized rats. Using a sensitive and specific radioimmunoassay (RIA), alphaMSH has been found in a number of brain regions in intact rats. The standard curves of synthetic alphaMSH and the dilution curves for pars intermedia nervosa (PIN), pars distalis (PD), hypothalamus and thalamus extracts were strictly parallel. The alphaMSH concentrations were measured in PIN (6,225 +/- 962 ng/mg wet tissue); PD (12.5 +/- 1.41 ng/mg); pineal (380 +/- 29 ng/g wet tissue); hypothalamus (645 +/- 161 ng/g) and thalamus (33.3 +/- 5.26 ng/g). In rats hypophysectomized for 1 or 2 months, the highest concentrations of immunoreactive alphaMSH were found in pineal (353 +/- 140 ng/g wet tissue), hypothalamus (85.8 +/- 14.1 ng/g) and thalamus (39.8 +/- 13.9 ng/g). Hypophysectomy significantly reduced hypothalamic MSH content and concentration but did not alter MSH concentration in pineal and thalamus. From these results, we conclude that hypothalamic alphaMSH is, in part, of hypophyseal origin while pineal and thalamus alphaMSH does not originate from the pituitary. After Sephadex G-25 gel filtration, synthetic alphaMSH and PIN extracts showed a single peak of both bioactive and immunoreactive alphaMSH. In the same conditions, extracts from the 5 brain regions studied in hypophysectomized rats chromatographed as a single peak of immunoreactive MSH but as 2 peaks of apparent bioactive MSH, 1 concident with synthetic alphaMSH and the other far after the salt volume. We conclude that alphaMSH is found in a number of brain areas and its presence after hypophysectomy would indicate synthesis within the central nervous system.
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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 | 0.001 | 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 | 0.000 |
| 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".