This article presents a review of the role of the sympathetic activity in ovarian pathologies affecting reproductive function. We provide a succinct outline of the findings of our group in this area. The participation of stress as an etiological factor for ovarian pathologies throughout animal models and data in patients with polycystic ovary syndrome give strong support for participation of sympathetic nerves in the ovary function both in normal and pathological status.

Background: Depletion of ovarian follicles is associated with the end of reproductive function in ageing females. Recently, it has been described that this process parallels increases in the concentration of norepinephrine (NE) in the rat ovary. In sexually mature rats, experimentallyinduced increases in the sympathetic tone of the ovary is causally related to ovarian cyst formation and deranged follicular development. Thus, there is a possibility that increased ovarian NE concentrations represent changes in the activity of sympathetic nerves, which consequently participate in the process of ovarian cyst formation observed during ageing in the human and experimental animal models.

A substantial fraction of the noradrenergic innervation targeting the mammalian ovary is provided by neurons of the celiac ganglion. Although studies in the rat have shown that noradrenergic nerves reach the ovary near the time of birth, it is unknown how the functional capacity of this innervation unfolds during postnatal ovarian development. To address this issue, we assessed the ability of the developing ovary to incorporate and release (3)H-norepinephrine. Incorporation of (3)H-norepinephrine was low during the first 3 wk of postnatal life, but pharmacological inhibition of norepinephrine (NE) neuronal uptake with cocaine showed that an intact transport mechanism for NE into nerve terminals is already in place by the first week after birth. Consistent with this functional assessment, the mRNA encoding the NE transporter was also expressed in the celiac ganglion at this time. During neonatal-infantile development [postnatal (PN) d 5-20], the spontaneous, vesicle-independent outflow of recently taken up NE was high, but the NE output in response to K(+)-induced depolarization was low. After PN d 20, spontaneous outflow decreased and the response to K(+) increased markedly, reaching maximal values by the time of puberty. Tyramine-mediated displacement of NE stored in vesicles, which displace vesicular NE, showed that vesicle-dependent NE storage becomes functional by PN d 12 and that vesicular release increases during the juvenile-peripubertal phases of sexual development. These results indicate that vesicular release of NE from ovarian noradrenergic nerves begins to operate by the third week of postnatal life, becoming fully functional near the time of puberty.

Catecholamines present in the mammalian ovary are involved in many normal aspects of ovarian functions, including initial follicle growth, steroidogenesis, and pathological states such as polycystic ovary syndrome. Sympathetic nerve fibers are the largest source of norepinephrine (NE), but not the only one. Surgical denervation of the rat ovary reduces, but does not eliminate, the ovarian content of NE. The aim of this work was to explore which intraovarian cells may participate in the ovarian NE homeostasis and the mechanisms involved. It was found that denervated rat ovaries can take up NE and cocaine considerably, decreased its uptake, suggesting involvement of catecholamine transporters. Granulosa cells of rat ovarian follicles present dopamine transporter and NE transporter. Their functionality was confirmed in isolated rat granulosa cells while cocaine blocked the uptake of NE. Furthermore, the presence of the vesicular monoamine transporter 2, together with the exocytotic protein (synaptosome-associated protein of 25 kDa) in granulosa cells, implies catecholamine storage and regulated release. Regulated calcium-dependent release of NE was shown after depolarization by potassium, implying all neuron-like cellular machinery in granulosa cells. These results in rats may be of relevance for the human ovary because dopamine transporter, NE transporter, vesicular monoamine transporter 2, and synaptosome-associated protein of 25-kDa protein and mRNA are found in human ovarian follicles and/or isolated granulosa cells. Thus, ovarian nonneuronal granulosa cells, after taking up catecholamines, can serve as an intraovarian catecholamine-storing compartment, releasing them in a regulated way. This suggests a more complex involvement of catecholamines in ovarian functions as is currently being recognized.

Polycystic ovary syndrome (PCOS) is characterized by the presence of hyperandrogenism and an increased follicular mass probably determined by deregulation of locally produced factors. Anti-Müllerian hormone (AMH) is a glycoprotein that inhibits follicular recruitment and determines the size of the follicular pool. To evaluate the role of androgens in the regulation of AMH expression in bovine granulosa cells from small follicles, granulosa cells from 3 to 4 mm follicles were isolated and incubated in basal culture media, or in media containing testosterone (T) at 10(-5)M, T 10(-8)M, or estradiol (E2) at 150 ng/ml for 48 h. AMH mRNA levels of these cells were determined using real-time PCR (RT PCR). AMH protein levels and E2 were determined in cell-conditioned media. A 3.4-fold decrease in AMH mRNA levels was observed in granulosa cells exposed to T 10(-5)M (P = 0.03, n = 5), but not in cells exposed to T 10(-8)M. AMH protein levels showed a 1.8-fold reduction in cell-conditioned media from cells exposed to T 10(-5)M (P = 0.01, n = 5), without significant changes in the group exposed to T 10(-8)M. Cells treated with E2 150 ng/ml showed no change in AMH protein levels. We propose that AMH expression is modulated by androgens in bovine granulosa cells from small follicles. Thus, it is possible to speculate that androgens, by inhibiting AMH expression, may promote follicle recruitment, increasing the early growing follicular pool. This new mechanism may have implications for the understanding of PCOS pathophysiology.