Parathyroid Hormone Contributes to Regulating Milk Calcium Content and Modulates Neonatal Bone Formation Cooperatively with Calcium
Bibliographic record
Abstract
To determine whether PTH and calcium (Ca) interact in neonatal bone formation, female lactating mice either heterozygous (PTH(+/-)) or homozygous (PTH(-/-)) for targeted deletion of the pth gene were fed either a normal (1% Ca, 0.6% phosphate) or high-Ca diet (2% Ca and 0.4% phosphate). Dietary effects on milk Ca content and Ca-regulating hormones were determined in dams, and the effects of milk content were assessed on bone turnover in 3-wk-old pups. On the normal diet, milk Ca and 1,25-dihydroxyvitamin D(3) levels were lower, but milk PTH-related protein levels were higher in the PTH(-/-) dams compared with the PTH(+/-) dams. On the high-Ca diet, milk Ca levels were higher, but milk 1,25-dihydroxyvitamin D(3) and PTH-related protein levels were lower in both PTH(+/-) and PTH(-/-) dams. In pups fed by PTH(-/-) dams compared with pups fed by PTH(+/-) dams on normal diets, bone mineral density, trabecular bone volume relative to tissue volume, and the number of osteoblasts were reduced in both PTH(+/-) (32.5 +/- 1.2 vs. 39.6 +/- 1.5 mg/cm(2), P < 0.05; 23.3 +/- 1.6 vs. 29.2 +/- 2.8%, P < 0.01; and 94.2 +/- 8.2 vs. 123.5 +/- 3.5/mm(2), P < 0.01, respectively) and PTH(-/-) (20.4 +/- 0.9 vs. 27.0 +/- 1.2 mg/mm(2), P < 0.05; 16.8 +/- 1.9 vs. 19.3 +/- 2.1%, P < 0.05; and 48.6 +/- 7.9 vs. 90.5 +/- 8.6/mm(2), P < 0.01, respectively) pups but were lower in the PTH(-/-) pups compared with the PTH(+/-) pups. In contrast, in pups fed by either PTH(+/-) or PTH(-/-) dams on the high-Ca diet, bone mineral density, bone volume/tissue volume, and osteoblast numbers were significantly higher, in both PTH(+/-) (50.5 +/- 1.7 vs. 58.7 +/- 2.0 mg/mm(2), P < 0.05; 37.9 +/- 5.2 vs. 46.1 +/- 5.1, P < 0.05; and 120.5 +/- 9.2 vs. 159.3 +/- 14.7/mm(2), P < 0.01, respectively) and PTH(-/-) (33.0 +/- 1.2 vs. 47.5 +/- 2.2 mg/mm(2), P < 0.001; 23.8 +/- 3.1 vs. 35.9 +/- 2.0, P < 0.05; and 78.7 +/- 10.1 vs. 99.8 +/- 13.6/mm(2), P < 0.05, respectively), and were highest in the PTH(+/-) pups fed by the PTH(+/-) dams on the high-Ca diet. These results indicate that PTH can modulate Ca content of milk, and that PTH and Ca can each exert cooperative roles on osteoblastic bone formation in the neonate.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".