| Abstract No.: | B-E2162 |
| Country: | Canada |
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| Title: | EFFECT OF MATERNAL CARE ON THE FEMALE OFFSPRING PHOSPHORYLATED ESTROGEN RECEPTOR ACTIVATION IN THE RAT. |
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| Authors/Affiliations: | 1 Nicole M. Cameron*; 2 Christian Caldji; 2 Josie Diorio; 1 Michael Meaney;
1 McGill University, Montreal, QC, Canada
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| Content: | Background: Maternal care influences the development of neuroendocrine system and sexual behaviors in rats. High and Low licking and grooming (LG) mothers and their female offspring differ in hypothalamic-pituitary-gonadal (HPG) function, in sexual receptivity and in the expression of estrogen-receptor alpha (ER alpha). High females show lower levels of gonadal hormones, less receptivity and increased ERalpha expression in the medial preoptic area (MPOA). Estrogen binding increases phosphorylation of ER alpha primarily at serine-118, which facilitates the recruitment of co-activators enhancing ER-mediated transcription. Thus, levels of ER alpha phosphorylation at serine-118 may provide a biologically relevant indication of ER alpha activation. A preliminary study using Western blotting revealed an expected increase in preoptic area serine-118 pER alpha in estrogen-treated ovariectomized animals compared with ovariectomy alone. Objective: The aim of this study was to examine phosphorylated (p) ER alpha activation in the anteroventral periventricular nucleus (AVPVn) an area known to be involved in the control of the HPG axis, using immunocytohistochemistry (ICC).
Methods: The samples were obtained from High and Low female offspring that were ovariectomized (with low estrogen replacement) and 14 days later received estrogen (10 ug) or sesame oil (control). Twenty-four h later, the brains were collected and used for pER alpha immunocytochemistry. Results: The ICC showed that ovariectomized females had an increased number of pER alpha-labeled cells in the AVPVn following acute treatment with 10 µg of estrogen. There was also a significant effect of maternal care across both treatment conditions (i.e., ovariectomy ± acute estrogen treatment) the number of pER alpha-labeled cells in the AVPVn was greater in the offspring of Low compared to High LG mothers. Conclusion: This finding is consistent with that of an increased level of ER alpha expression in the MPOA, and suggests that the differences in ER alpha expression in the AVPVn could mediate, in part, the differences in HPG function and thus sexual receptivity in the female offspring of High and Low LG mothers. |
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