Sexual Dimorphism in the Growth Hormone and Insulin-Like Growth Factor Axis at Birth
Bibliographic record
Abstract
In rodents and humans there is a sexually dimorphic pattern of GH secretion that influences the serum concentration of IGF-I. Pattern differences can be identified in children, but it is not known how early this difference is established. We studied the plasma concentrations of IGF-I, IGF-II, IGF-binding protein-3 (BP-3), and GH in cord blood taken from the offspring of 1650 singleton Caucasian pregnancies born at term and related these values to birth weight, length, and head circumference. Pregnancies complicated by preterm delivery, antepartum hemorrhage, pregnancy-induced hypertension, preeclampsia, or gestational diabetes and where cigarette smoking continued were excluded, resulting in a cohort of 987. Cord plasma concentrations of IGF-I, IGF-II, and IGFBP-3 were influenced by factors influencing birth size: gestational age at delivery, mode of delivery, maternal height, and parity of the mother. Plasma GH concentrations were inversely related to the plasma concentrations of IGF-I and IGFBP-3; 10.2% of the variability in cord plasma IGF-I concentration and 2.7% for IGFBP-3 was explained by sex of the offspring and parity. None of the factors, apart from maternal height, influenced cord serum IGF-II concentrations (adjusted r(2) = 1%). Sex of the baby, mode of delivery, and parity influenced cord serum GH concentrations (adjusted r(2) = 2.6%). Birth weight, length, and head circumference measurements were greater in males than females (P < 0.001). Mean cord plasma concentrations of IGF-I (males, 66.4 +/- 1.2 micro g/liter; females, 74.5 +/- 1.3 micro g/liter; P < 0.001) and IGFBP-3 (males, 910 +/- 13 micro g/liter; females 978 +/- 13 micro g/liter; P < 0.001) were significantly lower in males than females. Cord plasma GH concentrations were higher in males than females (males, 30.0 +/- 1.2 mU/liter; females, 26.9 +/- 1.1 mU/liter; P = 0.05), but no difference was noted between the sexes for IGF-II (males, 508 +/- 6 micro g/liter; females, 519 +/- 6 micro g/liter; P = NS). After adjustment for gestational age, parity, and maternal height, cord plasma concentrations of IGF-I and IGFBP-3 along with sex explained 38.0% of the variability in birth weight, 25.0% in birth length, and 22.7% in head circumference. These data demonstrate that in a group of singleton Caucasian babies born at term, cord plasma IGF-I, IGFBP-3, and GH concentrations relate to birth size, with evidence for sexual dimorphism in the GH-IGF axis.
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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) | 0.000 | 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".