Spam1 (PH-20) Expression in the Extratesticular Duct and Accessory Organs of the Mouse: A Possible Role in Sperm Fluid Reabsorption1
Bibliographic record
Abstract
A widely conserved sperm antigen, the sperm adhesion molecule 1 (SPAM1 or PH-20) is a glycosylphosphatidyl inositol-linked protein with multiple roles in mammalian fertilization. It has been shown to be dually expressed in testis and epididymis and this is conserved in the four species (mouse, rat, macaques, humans) that have been studied to date. Here, we report Spam1 RNA and protein expression in the murine vas deferens and efferent ducts. In situ hybridization and immunohistochemistry indicate that transcript and protein are distributed in the nonciliated epithelial cells and that the efferent ducts have the most intense staining of all three regions of the excurrent ducts. Spam1 products were also present in the accessory organs, the prostate, and seminal vesicles and its fluid. Using hyaluronic acid substrate gel electrophoresis, hyaluronidase activity at pH 7.0 was detected in the vas deferens but was absent from the efferent ducts, the prostate, and the seminal vesicles/fluid. This suggests that Spam1 may play a nonenzymatic role in these organs. In the efferent ducts, where Spam1 is enriched in the apical (but not basolateral) membrane of nonciliated cells, it is likely to play a role in sperm concentration, which is the established function of that organ.
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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) | 0.002 | 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".