Differential Control of the Release of Pro-Opiomelanocortin-Derived Peptides from the Pars intermedia of the Rat Pituitary
Bibliographic record
Abstract
The pars intermedia (PI) of the adenohypophysis synthesizes pro-opiomelanocortin, which, through post-translational processing, gives rise to a group of chemically related peptides, including αMSH, ACTH, CLIP, LPHs and endorphins. We investigated the control of release of these peptides using an in vitro system. We perifused either acutely dispersed rat PI cells or intact neurointermediate lobes (NI). Perifusion medium and cell extracts were subjected to a series of bioassays (BA) and radioimmunoassays (RIA) (including MSH-BA, αMSH-RIA, ACTH-BA, ACTH-RIA, LPH-RIA) and a receptor-binding assay for morphine-like activity (MLA). The relative amounts of release of the various peptide activities was examined under basal and stimulated conditions. Under basal conditions, intact NI released approximately equal amounts of αMSH immunoactivity, MSH bioactivity and MLA, slightly less ACTH and LPH immunoactivity and far less ACTH bioactivity. Relative to αMSH immunoactivity, the rate of release of ACTH bioactivity decreased in the course of an experiment while the release of the other peptide activities increased. The peptide activities were released from dispersed PI cells in relative amounts similar to those from intact NI. The relative amounts of peptide activities contained in extracts of dispersed PI cells differed from the amounts released such that when compared to αMSH immunoactivity, the release of LPH and ACTH immunoactivities and MLA is 3–4 times greater while the release of ACTH bioactivity is one-half. Serotonin (10–7–10–5M) markedly stimulated the release of ACTH bioactivity from both dispersed PI cells and intact NI in a dose-related manner. Serotonin had a smaller stimulatory effect on the release of αMSH and LPH immunoactivity but had no effect on the release of MLA and ACTH immunoactivity. These observations indicate that there is differential control of the release of POMC-derived peptides from the rat PI.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".