Evidence map›Paper›PMID 40369718›Full record

ArticleJournal of neuroendocrinology2025

Litter sex composition influences plasma prolactin levels but not the melanin-concentrating hormone immunoreactive neurons in the medial preoptic area of late lactating Long-Evans rats.

Ammir Y Helou, Camila de Carvalho, Larissa A do Carmo, Jackson C Bittencourt

Abstract read
In one paragraph

Article in Journal of neuroendocrinology, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

Ammir Y HelouLaboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil.ORCID 0000-0002-6740-4283
Camila de CarvalhoLaboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil.
Larissa A do CarmoLaboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil.
Jackson C BittencourtLaboratory of Chemical Neuroanatomy, Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil.ORCID 0000-0002-8908-6474

Funding

Conselho Nacional de Desenvolvimento Científico e Tecnológico 404806/2021-0Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorFundação de Amparo à Pesquisa do Estado de São Paulo 2016/02224-1Fundação de Amparo à Pesquisa do Estado de São Paulo 2023/02531-5
6 · The paper itself

Abstract

This study examines the influence of litter sex composition on melanin-concentrating hormone immunoreactive (MCH-ir) neurons in the ventromedial medial preoptic area (vmMPOA) and on plasma prolactin levels in lactating rats. MCH is a critical regulator of maternal behavior and displays sexual dimorphism within the MPOA, making it an important target for understanding neuroendocrine adaptations in lactation. Prolactin, a pivotal hormone in lactation and maternal care, was also assessed to elucidate its interaction with litter sex composition. Thirty lactating female rats were divided into five experimental groups based on litter sex composition: all-male (10 male pups), all-female (10 female pups), balanced control (five male and five female pups), predominantly male (seven male and three female pups), and predominantly female (three male and seven female pups). On post-partum day 19 (PPD19), the dams were euthanized for biological analysis. Blood samples were collected for plasma prolactin quantification, and the brains were processed to analyze MCH-ir neurons in the vmMPOA. Results showed no significant differences in food and water intake or the number of MCH-ir neurons in the vmMPOA among experimental groups. However, significant variation in prolactin levels was observed, with the all-male offspring group exhibiting the highest levels (mean prolactin level 23.9 ng/mL, p < .001), followed by the all-female group (20.3 ng/mL, p < .01), compared to the control group (14.3 ng/mL). Additionally, the all-male group showed a reduction in body weight gain. These results suggest that although litter sex composition does not alter the number of MCH-ir neurons in the vmMPOA, it significantly impacts maternal prolactin levels. This differential prolactin regulation may reflect distinct physiological demands or caregiving behaviors imposed by homogeneous litters, which could, in turn, influence maternal energy balance, lactation efficiency, and adaptive maternal responses. Understanding these sex-specific influences on maternal neuroendocrine function has important implications for comprehending maternal care dynamics and energy allocation during lactation.

Indexed as

Hypothalamic HormonesLactationLitter SizeMelaninsNeuronsPituitary HormonesPreoptic AreaProlactinAnimalsFemaleMaleRatsRats, Long-EvansSex CharacteristicsHypothalamic Hormonesmelanin-concentrating hormoneMelaninsPituitary HormonesProlactinlactationneuroendocrine regulationneuropeptidesreproductive physiologysex‐specific maternal adaptation

Identifiers

PMID40369718
PMCPMC12358198

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.