| Summary: | This thesis aimed to investigate luteolysis, and the functional and structural effects of maternal recognition of pregnancy in the primate corpus luteum. As progesterone production by the corpus luteum is dependent on luteinising hormone (LH) from the anterior pituitary gland, the expression and localisation of the LH/hCG receptor, key elements of the steroidogenic pathway and the progesterone receptor were studied. In addition, as the corpus luteum undergoes extensive tissue remodelling during its life-span, the expression and localisation of the major metalloproteinase enzymes, their specific tissue inhibitors and macrophages were investigated. In summary, a model system has been developed and used to study some of the genes and gene products involved in maintenance of the functional and structural integrity of the human corpus luteum. Functional luteolysis beings in the continued presence of the principal components of the steroidogenic pathway. However, as luteolysis progresses, expression of these components is reduced. Structural luteolysis is associated with increased expression of matrix metalloproteinases and an increase in tissue macrophage content. Exposure to hCG during maternal recognition of pregnancy maintains the steroidogenic pathway, and reduces the levels of matrix metalloproteinases and tissue macrophages. As LH receptors are localised to the granulosa-lutein cells this thesis concludes that the effect of luteal rescue on metalloproteinases and macrophages is mediated indirectly by activation or inhibition of specific products of these steroidogenic cells by hCG.
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