Satisfactory development of preantral follicles from humans and domestic ruminants in vitro remains elusive. The aims of this thesis were to use a serum-free culture system to identify regulators of early follicle and oocyte development. Preliminary experiments determined that bovine preantral follicles grow and produce increasing amounts of oestradiol throughout a six day culture period. Neither FSH nor IGF-1 significantly increased follicle diameter. However, FSH did promote follicular oestradiol secretion. The dissociation of follicular growth from steroidogenenic function indicated that measurement of follicular diameter may not be a reliable marker of physiological follicular development in vitro. In addition, stimulation of granulosa cells by FSH may result in inappropriate differentiation of these cells during the early stages of folliculogenesis. During follicular development, turnover and reconstruction of the basement membrane is facilitated and regulated by matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). When MMP-9 was secreted by prenatal follicles in vitro, the probability of follicles having healthy granulosa or theca cells at the end of culture was 0.85 and 0.60, respectively. If TMP-1 was released, there was a probability of 0.79 that the follicles would have healthy somatic cells. When TIMP-2 was detected, the probability of granulosa and theca cell health was 0.78 and 0.67, respectively. These results indicate that MMP-9 and TIMPs are related to follicular health, and can therefore be used as markers of follicular development. Ascorbic acid has been implicated in several processes associated with follicular development, including collagen biosynthesis, steroidogenesis and apoptosis. The effect of this vitamin on the development of bovine preantral follicles was investigated during a twelve day culture period. Ascorbic acid had no effect of follicular growth or oestradiol secretion. Serum addition from Day 0 stimulated follicular growth but compromised follicular integrity. By Day 12 of culture, a higher proportion of follicles remained intact in the presence of ascorbic acid in serum-free conditions, with significantly less granulosa and theca cell death than control follicles.