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Title: Regulation of oestrogen receptor mRNA in rat central nervous system
Author: Somponpun, Suwit J.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2000
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There are two principal oestrogen receptors (ER) characterised to date, ER-a and ER-b, the products of two distinct genes. Using quantitative in situ hybridisation histochemistry we first described the distribution of neurones expressing the messenger ribonucleic acid (mRNA) moieties for both types of ER in rat brain. We then investigated whether changes in the expression of these mRNA transcripts occur in response to hormonal manipulations as well as physiological stimulation in two discrete regions: the hippocampus, involved in memory, behaviour and regulation of the hypothalamo-pituitary-adrenal (HPA) axis and the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei, producing oxytocin and vasopressin, and autonomic regulation. Both ER-a and -b mRNAs were found to be expressed in the hippocampus, while only ER-b mRNA was localised in the PVN and SON. In the hippocampus, changes in the expression of both mRNA transcripts following gonadectomy were found in a region- and time-specific manner and displayed a sexual dimorphic pattern. However, replacement of E2 in overiectomised rats did not restore the basal level of expression indicating that factors other than the ligand itself are involved in mediating effects of gonadectomy. The expression of ER-b mRNA was found in regions containing oxytocin and vasopressin magnocellular neurones; expression in the PVN was low in the medial parvocellular neurones, projecting to the median eminence, but high in the ventral group of parvocellular neurones which project to brainstem and spinal cord. In the SON the greater ER-b mRNA signal found in female than in male rats was abolished by gonadectomy, but not restored or altered in intact male rats by E2 treatment. In the ventral parvocellular neurones, we found no sex difference in the expression of ER-b mRNA. Here, ovariectomy significantly increased the expression of ER-b mRNA. The expression of ER-b mRNA in both the magno- and parvo-cellular neurones was not changed at the end of pregnancy, when oestrogen secretion is maximal.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available