We found that F2 female heterozygotes for this allele showed, on average, impaired offspring survival when compared to females with either homozygote genotype (Fig. 3; P < 0.01). Peg3 hypothalamic expression is lower in LG/J females, but Oxt and FosB expression levels are not affected The levels of Oxt and FosB transcripts in the hypothalamus of SM/J and LG/J females on the second postpartum

day were similar between Inhibitors,research,lifescience,medical strains (P > 0.05) (Fig. 4). Alternatively, Peg3 transcripts were lower in the hypothalamus of female LG/J mice on the second day postpartum when compared to SM/J females (–37.4%, P < 0.01) (Fig. 4). In these samples, Ppia and Actb showed the Inhibitors,research,lifescience,medical most stable levels (M = 0.91, geNorm applet) and were therefore used to normalize transcript levels for the candidate genes. Transcript levels for all tested control genes were similar for both strains (Ppia: 0.43 ± 0.06 vs. 0.41 ± 0.04; Actb: 0.28 ± 0.07 vs. 0.25 ± 0.04; and Hprt1: 0.61 ± 0.05 vs. 0.59 ± 0.05; n= 13 per group; SM/J vs. LG/J, respectively, P > 0.05). Figure 4 Oxt, FosB, and Peg3 transcript levels

in the hypothalamus of female mice on the Inhibitors,research,lifescience,medical second day postpartum. Chromosome 2 QTL candidate gene, Oxt, shows no significant differences in expression between SM/J and LG/J females. mRNA transcript levels for the chromosome … Discussion Caring for, feeding, and protecting pups after birth are the primary maternal behaviors responsible for Inhibitors,research,lifescience,medical offspring survival and growth in rodents (Lee et al. 1991). Nest building is a common maternal care that keeps pups together and confined in the first days of life allowing their temperature maintenance (Lynch 1994; Gaskill et al. 2011) and the close contact with their mother (Fleming et al. 1999). In the present study, we demonstrate that female mice of both SM/J and LG/J strains generally

build a nest before labor and maintain it after delivery. However, with respect to the quality of these nests in the postpartum period, SM/J females displayed more sophisticated nests using the material provided, in contrast to shallow Inhibitors,research,lifescience,medical and less elaborate nests built by LG/J dams. Generally, mothers show some response to sensorial stimuli after birth coming from pups (Rosenblatt 1975; Weber and Olsson 2008) and the Ki16425 presence of pups may reflect in postpartum nest building, as we may see through the higher complexity in the genetic architecture of postpartum than prepartum NEW ENGLAND JOURNAL OF MEDICINE nest-building behavior (B. Sauce, R. A. de Brito and A. C. Peripato, unpubl. data). Therefore, based on nest quality criteria, LG/J mothers showed impaired nest-building behavior. Milk provision is essential in mammals, so it is crucial that females provide food immediately after pups are born (Silver 1995). Most SM/J females exhibited milk ejection at the first day postpartum, but LG/J females had a one-day delay in milk letdown.