PTH Regulates Fetal Blood Calcium and Skeletal Mineralization Independently of PTHrP
Bibliographic record
Abstract
PTH and PTHrP both act in the regulation of fetal mineral metabolism. PTHrP regulates placental calcium transfer, fetal blood calcium, and differentiation of the cartilaginous growth plate into endochondral bone. PTH has been shown to influence fetal blood calcium, but its role in skeletal formation remains undefined. We compared skeletal morphology, mineralization characteristics, and gene expression in growth plates of fetal mice that lack parathyroids and PTH (Hoxa3 null) with the effects of loss of PTHrP (Pthrp null), loss of PTH/PTHrP receptor (Pthr1 null), and loss of both PTH and PTHrP (Hoxa3 null x Pthrp null). Loss of PTH alone does not affect morphology or gene expression in the skeletal growth plates, but skeletal mineralization and blood calcium are significantly reduced. In double-mutant fetuses (Hoxa3 null/Pthrp null), combined loss of PTH and PTHrP caused fetal growth restriction, limb shortening, greater reduction of fetal blood calcium, and reduced mineralization. These findings suggest that 1) PTH may play a more dominant role than PTHrP in regulating fetal blood calcium; 2) blood calcium and PTH levels are rate-limiting determinants of skeletal mineral accretion; and 3) lack of both PTH and PTHrP will cause fetal growth restriction.
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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 | 0.001 |
| 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".