References of "Galea, Liisa AM"
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See detailRole of coactivators SRC-1 and CARM1 in estrogen receptor-alpha and beta-dependent cell proliferation in the dentate gyrus of adult female rats
Charlier, Thierry ULg; Lieblich, Stephanie E; Pawluski, Jodi L et al

Poster (2007)

Nuclear receptors such as the estrogen receptors (ER) require the presence of coactivator proteins, such as the steroid receptor coactivator (SRC-1) and coactivator-associated arginine methyltransferase ... [more ▼]

Nuclear receptors such as the estrogen receptors (ER) require the presence of coactivator proteins, such as the steroid receptor coactivator (SRC-1) and coactivator-associated arginine methyltransferase (CARM1) to enhance the transcription of target genes. Importantly, in vitro work suggests that ER􀀁 and ER􀀂 differ in the ability to recruit coactivators such as SRC-1. For example, SRC-1 has a strong affinity for ER􀀁 and a weaker affinity for ER􀀂. Interestingly, both ER􀀁 and ER􀀂 are individually involved in estradiol-enhanced cell proliferation in the dentate gyrus of adult female rats. In addition, previous work suggests a role for CARM1 in cell proliferation and for SRC-1 in cell differentiation, therefore the present study aimed to determine whether proliferating cells in the dentate gyrus of the hippocampus co-express the coactivators SRC-1 and CARM1. We also aimed to determine whether ER􀀁 and ER􀀂 agonists would result in altered expression of SRC-1 and CARM1 in new proliferating cells in the dentate gyrus. To investigate this, adult female rats were ovariectomized and treated with either the ER􀀁 agonist Propyl-pyrazole triol (PPT), the ER􀀂 agonist diarylpropionitrile (DPN), estradiol benzoate (EB), or vehicle (CTRL). Rats were then injected with BrdU (200 mg/kg) and sacrificed 24 hours later. Preliminary data suggests that DPN, PPT and EB increase cell proliferation in the dentate gyrus compared to the vehicle-injected group. Interestingly, the number of proliferating cell expressing SRC-1 is similar in all groups, suggesting that neither of the ER agonists nor EB treatment affects the co-expression of BrdU+ cells with SRC-1. However, additional measurements are currently being done to investigate whether CARM-1 is differentially expressed in proliferating cells in the hippocampus following selective ER agonist treatment. [less ▲]

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See detailCorticosteroid-binding capacity, but not total corticosterone, is decreased during lactation in rat dams
Pawluski, Jodi L; Charlier, Thierry ULg; Hammond, Geoffrey L et al

Poster (2006)

The role of corticosterone on the hippocampal structure and function is well documented in male rats. More recently research has shown that chronically stressed female rats with elevated corticosterone ... [more ▼]

The role of corticosterone on the hippocampal structure and function is well documented in male rats. More recently research has shown that chronically stressed female rats with elevated corticosterone levels, exhibit significant dendritic alterations in the hippocampus and, paradoxically, enhanced learning and memory performance. Similar changes have been shown with first reproductive experience (primiparity) compared to further reproductive experience (multiparity). We have shown that at the time of weaning, primiparous rats exhibit altered hippocampal morphology (Pawluski and Galea, 2006), decreased hippocampal cell survival (Pawluski and Galea 2006), and improved reference memory performance (Pawluski et al, 2006) compared to multiparous and virgin female rats. Therefore, given the similarities to what has been shown in the chronically stressed virgin female rat, it seems plausible that corticosterone may play an active role in mediating the alterations seen in primiparous rats. The present study aimed to investigate whether there are differences in the level of free circulating corticosterone during late pregnancy and the postpartum period with reproductive experience. Total corticosterone and corticosteroid-binding capacity were assayed from serum in five groups of rats; multiparous, primiparous, pregnant-only, pup-exposed virgins, and nulliparous rats on 6 days (2 days during gestation: days 14 and 19, and 4 days during lactation; days 1, 5, 14, and 21, where applicable). Results show that total corticosterone level on postpartum day 1 was significantly elevated compared to all other days. In addition, primiparous and multiparous rats have significantly lower corticosteroid-binding capacity throughout lactation. This suggests that primiparous and multiparous rats have more free-circulating corticosterone during lactation. Further research is needed to determine the mechanism underlying the changes in hippocampal structure and function with primiparity. [less ▲]

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