Fetal exposure to excess glucocorticoid is unlikely to explain the effects of periconceptional undernutrition in sheep
Bibliographic record
Abstract
Periconceptional undernutrition alters fetal growth, metabolism and endocrinology in late gestation. The underlying mechanisms remain uncertain, but fetal exposure to excess maternal glucocorticoids has been hypothesized. We investigated the effects of periconceptional undernutrition on maternal hypothalamic-pituitary-adrenal axis function and placental 11beta-hydroxysteroid dehydrogenase type 2 (11betaHSD2) activity. Ewes received maintenance feed (N, n= 20) or decreased feed from -60 to +30 days from mating to achieve 15% weight loss after an initial 2-day fast (UN, n= 21). Baseline plasma samples and arginine vasopressin (AVP)-corticotrophin-releasing hormone (CRH) challenges were performed on days -61, -57, -29, -1, +29, 33, and 49 from mating (day 0). Maternal adrenal and placental tissue was collected at 50 days. Baseline plasma levels of adrenocorticotrophic hormone (ACTH) and cortisol decreased in the UN group (P < 0.0001). ACTH response to AVP-CRH was greater in UN ewes during undernutrition (P= 0.03) returning to normal levels after refeeding. Cortisol response to AVP-CRH was greater in UN ewes after the initial 2-day fast, but thereafter decreased and was lower in UN ewes from mating until the end of the experiment (P= 0.007). ACTH receptor, StAR and p450c17 mRNA levels were down-regulated in adrenal tissue from UN ewes. Placental 11betaHSD2 activity was lower in UN than N ewes at 50 days (P= 0.014). Moderate periconceptional undernutrition results in decreased maternal plasma cortisol concentrations during undernutrition and after refeeding, and adrenal resistance to ACTH for at least 20 days after refeeding. Fetal exposure to excess maternal cortisol is unlikely during the period of undernutrition, but could occur later in gestation if maternal plasma cortisol levels return to normal while placental 11betaHSD2 activity remains low.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".