The Fallopian tubes are organs of transport and the tubal fluid nourishes the embryo during this time. Their role, however, has largely been neglected since the development of in vitro fertilisation. Studies of tubal physiology have been limited by the relative inaccessibility of the tubes, problems with collecting neat tubal fluid and difficulties in developing tests which reliably assess tubal function rather than tubal patency. This thesis sets out to validate the technique of in vitro vascular perfusion of the Fallopian tubes and to demonstrate that it is a reproducible technique which can be used for studying tubal physiology and of defining the environment to which the gametes and pre-implantation embryo are exposed. These experiments show that the Fallopian tubes can be perfused for up to 2 hours without damage and loss of viability. In this time, sufficient fluid can be collected for analysis of glucose, pyruvate, lactate and amino acids. This is the first report of amino acid composition in human tubal fluid. Using the validated technique, tubal fluid production was shown to vary with the menstrual cycle. Greater volumes were produced in the proliferative and early secretory phases. Fluid production was also stimulated by isoproterenol and suppressed by dibutyryl cyclic-AMP. The concentrations of glucose, pyruvate and lactate in native tubal fluid were 0.93 mM (+/- 0.15), 0.28 mM (+/-0.1), and 6.5 mM (+/- 0.6) respectively. All 17 amino acids tested were present in low concentrations with alanine and arginine the most concentrated irrespective of the phase of the menstrual cycle. Tubal muscle activity in response to isoproterenol was studied by monitoring isometric contractions via a Gallenkamp 2-channel recorder, Isoproterenol reduced the frequency of muscle contractions in both longitudinal and circular layers irrespective of the hormonal status of the women. Amplitude of contractions in the circular layer was increased by isoproterenol.

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The ovarian follicle is an individual functional unit that provides the optimal environment for the oocyte within to develop. This thesis outlines the research in the field of ovarian follicular dynamics that has already been established, and further develops these findings to explore in greater detail the relationship between the oocyte and its environment, both in an in vitro and in vivo setting, using a variety of species. The first major research area involved studying the role of oocyte-secreted factors, which was examined using a series of dose response experiments. These were performed using an ovine granulosa cell culture model, and elucidated a possible role for a collaborative action of BMP15 and GDF9 in the promotion of oestradiol synthesis, while inhibiting production of progesterone in this species. This finding was then further investigated using an ovine in vivo immune-neutralisation study, the endocrine and histological results of which confirmed these findings in a proportion of these animals, although this study was limited by the animals appearing to have been in seasonal anoestrus. The second major topic that was investigated was based around the ovarian microenvironment, in terms of angiogenesis and hypoxia. Again, ovine granulosa cell cultures were used, in this instance to examine the effect of hypoxic conditions on steroid hormone production. These experiments indicated that somatic cell steroid hormone production is likely to be compromised by a hypoxic environment, and therefore that the provision of oxygen through a local blood supply may be a vital requirement for these cells. To investigate the relevance of studying ovarian blood supply and physiology in a clinical setting, perfusion studies were carried out based on a series of bovine phantom experiments, which were used to study the effect of varying flow rate on the parameters routinely measured using this technology. The routine clinical ultrasonographic methods of ovarian assessment such as 4D ViewTM, SonoAVCTM and VOCAL were also examined, based on bovine phantom experiments, revealing possible weaknesses in the data provided by ultrasound that are increasingly relied upon in the clinical setting. Finally, a clinical trial was carried out to try and encompass all of the findings of the in vitro and in vivo work, in order to place these theories into context in a human IVF setting. This work was unfortunately limited severely by a lack of patient numbers, but some interesting results were observed with regard to oocyte developmental potential relationships with follicular fluid and somatic cell factors, as well as ultrasound measures of peri-follicular blood supply.