F ovarian sex-steroid receptors. Similarly, ovarian ER-a and ER-b were overexpressed
F ovarian sex-steroid receptors. Similarly, ovarian ER-a and ER-b were overexpressed in rats that received low maternal care, whereas AR levels did not differ between the groups (Figures 3A, B).Cell proliferation index (Ki-67) in UCh offspringImmunoreactivity for Ki-67 in the granulosa cells of the primary, preantral, antral and mature follicles was significantly higher in animals receiving low maternal care during early postnatal life. In contrast, growing follicles did not show significant 4-DeoxyuridineMedChemExpress Zebularine differences between the groups (Table 3; Figure 4).Discussion In the rat, variations in maternal care are associated with individual differences during the development of the neuroendocrine and reproductive system, most prominently in the females [34-36]. Evaluation of maternalTable 2 Duration of estrous cycles in the UCh female offspring (n = 10/group)Parameters Estrous cycle duration (days) Frequency in proestrus (days) Frequency in estrus (days) Frequency in metestrus (days) Frequency in diestrus (days) UChA Offspring 4.00 ?0.10 5.30 ?0.15 5.50 ?0.16 0.70 ?0.26 9.50 ?0.16 UChB Offspring 5.86 ?0.30* 3.63 ?0.15* 4.83 ?0.56 3.36 ?0.43* 9.18 ?0.*p PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/28506461 < 0.05. Student's t-test. Values are expressed as means ?SEMcare during the first 10 days postpartum revealed significant differences in maternal-infant interaction between the UCh lactating rats. UChA mothers showed higher frequencies of carrying, licking/grooming, arched-back nursing with L/G and arched-back nursing cares. However, the analysis of passive nursing and simple contact with offspring did not show significant differences. Two distinct strategies of maternal care were categorized: first, lactating UChA females offered high levels of mother-offspring contact, exhibited high infant excitement frequency (licking/grooming) and showed devotion to offspring (nutrition and heating); second, UChB mothers showed low levels of excitement and dedication to offspring and high frequencies of maternal rejection. Therefore, female UCh may be high-care (UChA mother) or low-care (UChB mother), similar to other rodent species [7,37,38]. The onset of maternal care in postpartum lactating PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/28388412 females reflects hormone concentrations and the densities of hypothalamic receptors that stimulate and prepare the animal, beginning during the prenatal period [39]. Differently from UChB mothers, UChA mothers were more dedicated and busy during the execution of maternal care, evidencing the highest plasma corticosterone levels at the end of lactation. It is well known that mothers treated with moderate concentrations of exogenous corticosterone have increased frequency of licking/grooming and arched-back nursing care activities [40,41]. This moderate increase in maternal corticosterone is fundamental to the offspring, as it induces the appropriate development of the aminoacidergic and serotoninergic systems and maturation of hypothalamic-Amorim et al. Reproductive Biology and Endocrinology 2011, 9:160 http://www.rbej.com/content/9/1/Page 7 ofFigure 2 Hormonal profile of UCh mothers and offspring after variation of maternal care in the postpartum period. (A) Plasma corticosterone levels in the UCh mothers (ng/mL); (B) Plasma corticosterone levels in the UCh offspring (ng/mL); (C) Plasma FSH levels in the UCh offspring (ng/mL); (D) Plasma LH levels in the UCh offspring (ng/mL); (E) Plasma E2 levels in the UCh offspring (pg/mL) and (F) Plasma P4 levels in the UCh offspring (ng/mL). Values are expressed as means ?SEM. n = 10 animals.