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dc.contributor.authorSneddon, Sharon Fultonen
dc.date.accessioned2018-03-29T12:20:20Z
dc.date.available2018-03-29T12:20:20Z
dc.date.issued2005en
dc.identifier.urihttp://hdl.handle.net/1842/29373
dc.description.abstracten
dc.description.abstractThe testis has two main functions, the synthesis of steroid hormones and the production of spermatozoa. The adult testis contains three main somatic cell types, namely Sertoli cells, Leydig cells and peritubular myoid cells, as well as germ cells at all stages of maturation. Interactions between these cells and the steroid hormones produced by the testis are responsible for the regulation and maintenance of spermatogenesis and fertility. Depletion or exposure to high levels of oestrogens, or androgens, both have an adverse impact on male reproductive function. In the testis, as well as in other organs, steroid hormone action is mediated by ligand-activated receptors. A single androgen receptor (AR) and two oestrogen receptors (ERα and ERß) have been identified.en
dc.description.abstractThe aims of this study were to investigate the role of steroid hormones, in particular oestrogens, in murine spermatogenesis. A major focus of these investigations was the role played by ERß in the modulation of germ cell and somatic cell function. Studies were conducted both using a transformed murine Sertoli cell line (SK11), which has maintained a differentiated Sertoli cell phenotype and spermatogonial stem cells, which were successfully isolated and characterised. Steroid hormone receptor status, steroid responsiveness and the impact of targeted deletion using RNAi were all assessed.en
dc.description.abstractCharacterisation of the SKI 1 cell line, which was cultivated under conditions which maintained them in an undifferentiated or differentiated state, revealed they retain many features of Sertoli cells in vivo. ERß mRNA and protein were shown to be expressed in the SK11 cells both in the undifferentiated and differentiated states. Transient transfections using ERß or ARE-luciferase reporter constructs and stimulation with steroid ligands revealed that the cells contained functional steroid hormone receptors. Knockdown of ER|3 mRNA and protein was achieved in the cells after targeted deletion using a short hairpin RNAi containing vector; this blunted the ability of the cells to respond to oestrogen.en
dc.description.abstractIsolation of spermatogonial stem cells was carried out using immunomagnetic beads. The stem cell population were shown to express Oct-4 and GFRα-1 mRNAs, both of which are stem cell markers, but not c-kit, which is a marker of differentiated germ cells. Taqman Q-RT-PCR demonstrated that the stem cell population expressed ERß. Oct-4 mRNA expression was shown to be reduced by RNAi; this induced the cells to undergo differentiation in vitro characterised by increased expression of c-kit.en
dc.description.abstractIn conclusion, the current studies have extended our understanding of the impact of steroid hormones on testicular function and have revealed for the first time that spermatogonial stem cells are ERß positive. The SKI 1 cell line has been found to provide a suitable model system for the study of steroid regulation of Sertoli cell function. In addition, the use of RNAi has provided an exciting new avenue by which to manipulate gene expression levels in testicular germ and somatic cells.en
dc.publisherThe University of Edinburghen
dc.relation.isreferencedbyAlready catalogueden
dc.subjectAnnexe Thesis Digitisation Project 2018 Block 17en
dc.titleOestrogen regulation of gene expression in male germ cells and Sertoli cellsen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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