Endocrine Communication between Conceptus and Mother: Placental Lactogen Stimulation of Maternal Behavior
Bibliographic record
Abstract
The possible role of the conceptus in stimulating the onset of maternal behavior through its secretion of placental lactogens and their passage into the brain was investigated in female rats. In the first study, significant mitogenic activity in the Nb2 lymphoma cell bioassay was detected in cerebrospinal fluid (CSF) samples collected by push-pull perfusion from rats on days 12-21 of pregnancy, coincident with the establishment of placental function. In contrast, mitogenic activity was absent from CSF in lactating and gonadectomized, virgin females. In a second study the mitogenic activity in day 12 pregnant samples was neutralized 71% with antibodies to rat placental lactogen-I (rPL-I) and > 90% with a combination of antibodies to rPL-I plus rPL-II. In contrast, activity on day 21 of pregnancy, 1 day prepartum, was reduced by antibodies to rPL-II (> 85%), but not by antibodies to rPL-I, indicating that the predominant lactogen in the CSF prepartum is rPL-II. The behavioral actions of placental secretions were assessed in the third experiment by infusing recombinant rPL-I and purified rPL-II directly into the medial preoptic area of the brain of steroid-primed, nulliparous rats. Latencies to respond maternally to foster young were significantly reduced in rPL-I- and rPL-II-treated rats (2- to 3-day latencies) when compared with latencies in control females (5- to 6-day latencies). Thus, the conceptus through its secretion of rPLs which apparently gain access to the CSF helps to prime the pregnant female's brain to respond maternally at the end of gestation. This endocrine communication between the developing conceptus and pregnant female appears to be an important part of the biological system which helps to establish successful maternal care.
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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 | 0.000 |
| 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".