The physiological role of ovarian oxytocin has been much debated since its (re)discovery at the beginning of the decade (Wathes, 1984). As a neuropeptide secreted in abundance from a non-neural tissue, ovarian oxytocin has been a good example of the 'ectopic' endocrinology discussed by Henderson (1987). As pointed out recently (Auletta, Jones & Flint, 1988), we are still only certain of its secretion in major quantities in domestic ruminants. For these species, much experimental evidence has accumulated at both the animal and tissue levels regarding the circumstances and mechanism of its secretion. The problem has been to define exactly what role it may play in the endocrinology of the reproductive cycle. Neither of the two main hypotheses put forward to account for the presence of oxytocin in the ovary has proved to be entirely satisfactory.
The first hypothesis proposes a paracrine role for oxytocin in the regulation of ovarian steroidogenesis.