Background: RFamide-related peptide-3 (RFRP-3) inhibits gonadotropin releasing hormone (GnRH) and luteinizing hormone (LH) secretion in rats. This study evaluates the effects of litter size and suckling intensity on RFRP mRNA expression in the dorsomedial hypothalamic nucleus (DMH) of rats.
Materials And Methods: A total of 32 pregnant and 4 non-lactating ovariectomized (control group) Sprague-Dawley rats were used in this experimental study. Lactating rats were allotted to 8 equal groups. In 3 groups, the litter size was adjusted to 5, 10, or 15 pups upon parturition. Dams were allowed to suckle their pups continuously until 8 days postpartum. In the other 3 groups, the litter size was adjusted to 5 pups following birth. These pups were separated from the dams for 6 hours on day 8 postpartum, after which the pups were allowed to suckle for 2.5, 5, or 7.5 minutes prior to killing the dams. In 2 groups, lactating rats with 10 and 15 pups were separated from their pups for 6 hours on day 8 postpartum. In these groups, the pups were allowed to suckle their dams for 5 minutes before the dams were killed. All rats were killed on day 8 postpartum and the DMH was removed from each rat. We evaluated RFRP mRNA expression using realtime polymerase chain reaction (PCR).
Results: The expression of RFRP mRNA in the DMH increased with increased litter size and suckling intensity compared to the controls. The effect of suckling intensity on the expression of RFRP mRNA was more pronounced compared to the litter size.
Conclusion: Increased litter size and suckling intensity stimulated RFRP mRNA expression in the DMH which might contribute to lactation anestrus in rats.
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http://dx.doi.org/10.22074/ijfs.2015.4554 | DOI Listing |
Anim Biotechnol
December 2025
Department of Plant, Soil and Food science, University of Bari, Aldomoro, Italy.
Variation in litter size (LS) in sheep is linked to genetic factors, including the Zona pellucida-3 (ZP3) gene, which plays a role in ovine reproductive processes. This study examined the association between ZP3 gene variations and LS in Kari sheep. Two groups of 160 Kari ewes were analysed: one consistently producing singletons and another producing twins, with occasional triplets.
View Article and Find Full Text PDFEcol Evol
January 2025
Department of Zoology, Fisheries, Hydrobiology and Apiculture, Faculty of Agronomy Mendel University in Brno Brno Czech Republic.
This study evaluates the response of ground beetle (Coleoptera: Carabidae) assemblage to forest management practices by integrating species composition, body traits, wing morphology and developmental instability. Traditional approaches that rely on averaged identity-based descriptors often overlook phenotypic plasticity and functional trait variability, potentially masking species-specific responses to environmental changes. To address this, we applied a three-layered analytical approach to address this gap, utilising ground beetle occurrence and morphological trait data from Podyjí National Park, Czech Republic.
View Article and Find Full Text PDFFront Toxicol
January 2025
Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.
Solid lipid nanoparticles (SLNs) have gained interest as drug delivery carriers due to their efficient cellular internalization and increased therapeutic effect of the loaded drug, with minimal side effects. Although recently several studies have shown the possibility to administer SLNs during pregnancy to vehicle mRNA to the placenta, data about the effect of premating exposure to SLNs on pregnancy outcome are scant. Considering that assumption of drug-delivering nanocarriers in reproductive age may potentially affect women's reproductive health, the aim of the present study was to evaluate whether repeated oral administration of SLNs to female mice prior to mating would influence key pregnancy outcomes.
View Article and Find Full Text PDFJ Dev Orig Health Dis
January 2025
Postgraduate Program in Physiological Sciences, State University of Londrina, Londrina, Parana, Brazil.
Nutritional status during the developmental periods leads to predisposition to several diseases and comorbidities, highlighting metabolic and reproductive changes throughout adult life, and in the next generations. One of the experimental models used to induce undernutrition is litter size expansion, which decreases the availability of breast milk to pups and delays development. This work evaluated the effects of maternal undernutrition induced by litter size expansion, a maternal undernutrition preconception model, on the metabolic and reproductive alterations of the offspring.
View Article and Find Full Text PDFSci Rep
January 2025
Key Laboratory of Genetics, Breeding and Reproduction of Grass-Feeding Livestock, Key Laboratory of Animal Biotechnology of Xinjiang, Ministry of Agriculture(MOA), Urumqi, 830026, Xinjiang, China.
CRISPR/Cas9 technology has been widely utilized to enhance productive performance, increase disease resistance and generate medical models in livestock. The FecB allele in sheep is a mutation in the BMPRIB gene, recognized as the first major gene responsible for the high fecundity trait in sheep, leading to an increased ovulation rate in ewe. In this study, we employed CRISPR/Cas9-mediated homologous-directed repair (HDR) to introduce a defined point mutation (c.
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