Growth hormone in neural tissues of the chick embryo
Bibliographic record
Abstract
Growth hormone (GH) gene expression predominantly occurs in the pituitary gland, although it also occurs in many extrapituitary sites, including the brain. The cellular location and ontogeny of neural GH production is, however, largely unknown. This has therefore been determined during chick embryogenesis. In chicks, the brain develops from the neural tube at embryonic day (ED) 3. At this age, the divisions of the brain (the telencephalon, diencephalon, mesencephalon, metencephalon and myelencephalon) have intense GH immunoreactivity (GH-IR) (detected by two polyclonal antibodies and a monoclonal antibody for chicken GH). The otic and optic vesicles were also strongly GH immunoreactive, as were the Vth (semi-lunar), VIIth (facial), VIIIth (acoustic) and IXth (glossopharyngeal) nerve ganglia. This GH-IR was specific for GH and was lost when the antibodies were preabsorbed with recombinant chicken GH. The widespread distribution of GH-IR in the neural tissues of ED 3 embryos was mirrored by the distribution of GH receptor (GHR) immunoreactivity, detected by an antibody raised against the chicken GHR. In ED 6/ED 7 embryos, the neural retina of the eye and the epithelial and lens fiber cells were intensely stained for GH-IR, as was Rathke's pouch and the wall of the diencephalon. In contrast, only a few scattered cells were immunoreactive in the surrounding mesoderm. At ED 14, the GH-IR in the brain was restricted to specific tissues and cells. For instance, immunoreactive cells were present in the molecular and pyramidal layers of the cerebral cortex, in the gray matter of the cerebellum, in the choroid plexus, and in the walls of the ventricles. In summary, GH- and GHR-like proteins are abundant in neural tissues of the chick during the first third of incubation, becoming discretely localized to specific tissues and cells during later incubation. The localization of GH and GHR in these tissues, prior to the ontogeny of plasma GH, suggests autocrine or paracrine roles for GH during early embryogenesis.
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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 | 0.001 |
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".