Biochemical Characterization and Immunocytochemical Localization of EM66, a Novel Peptide Derived from Secretogranin II, in the Rat Pituitary and Adrenal Glands
Bibliographic record
Abstract
Characterization of secretogranin II (SgII) mRNA in various vertebrates has revealed selective conservation of the amino acid sequences of two regions of the protein, i.e., the bioactive peptide secretoneurin and a flanking novel peptide that we named EM66. To help elucidate the possible role of EM66, we examined the occurrence as well as the cellular and subcellular distribution of EM66 in rat pituitary and adrenal glands by using a polyclonal antibody raised against the recombinant human EM66 peptide. High-performance liquid chromatography (HPLC) analysis of rat pituitary and adrenal extracts combined with a radioimmunoassay resolved EM66-immunoreactive material exhibiting the same retention time as recombinant EM66. In the rat pituitary, double-labeling immunohistochemical (IHC) studies showed that EM66 immunoreactivity (IR) was present in gonadotrophs, lactotrophs, thyrotrophs, and melanotrophs, whereas corticotrophs were devoid of labeling. EM66-IR was also observed in nerve endings in the neural lobe. Immunocytochemical staining at the electron microscopic level revealed that EM66-IR is sequestered in the secretory granules within gonadotrophs and lactotrophs. In the adrenal medulla, double IHC labeling showed that EM66-IR occurs exclusively in epinephrine-synthesizing cells. At the ultrastructural level, EM66-IR was seen in chromaffin vesicles of adrenomedullary cells. These results demonstrate that post-translational processing of SgII generates a novel peptide that exhibits a cell-specific distribution in the rat pituitary and adrenal glands where it is stored in secretory granules, supporting the notion that EM66 may play a role in the endocrine 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 | 0.000 | 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".