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Abstract. The aim of the present study was to determine changes in the density of sympathetic nerves in porcine ovaries with dexamethasone (DXM)-induced cysts and the alterations in steroidogenic activity and amounts of catecholamines in the affected gonads. Cystic ovaries were supplied by numerous sympathetic nerve fibers. The amount of noradrenaline in the cysts (fluid, wall) was significantly higher than in the large follicles of the control group. After DXM injections, the amounts of noradrenaline and adrenaline significantly increased in the walls of small and medium-sized follicles. In the cysts (fluid, wall) the levels of androgens and estrogens were significantly lower, whereas progesterone was higher in the cystic wall. DXM administration led to a significant increase in the estrone content in the fluid of small follicles. Moreover, a decrease in the amounts of progesterone and androgens was found in the follicular fluid and walls of medium-sized follicles. DXM injections resulted in a significant increase in the immunoexpression of P450scc and 3β-HSD in the cysts, a significant increase of P450scc in the follicles, and a decrease of 3β-HSD and P450arom. The present study shows that the DXM treatment leads to an increase in the density of intraovarian sympathetic nerves, paralleled by the amount of catecholamines, and that it is capable of changing the steroidogenic activity of porcine ovary bearing cysts. Thus, it appears possible that these events may be, at least partly, involved in the pathogenesis of this disorder.

Changes in both the morphology and the steroidogenic activity of porcine ovaries denervated surgically on day 12 of the oestrous cycle were studied. Neurectomy of the plexus and the superior ovarian nerves caused a dramatic reduction in the number (or even a disappearance) of dopamine-β-hydroxylaseand/or neuropeptide tyrosine-immunoreactive nerve terminals. On day 20 of the subsequent oestrous cycle, the number of small follicles increased (P < 0.01) and that of large follicles decreased (P < 0.05) in the denervated ovaries, as compared to the controls. Neurectomy led to a decrease in the level of progesterone (P 4 ; P < 0.001) and androstenedione (A 4 ; P < 0.01) in the fluid from small follicles, A 4 (P < 0.001) and testosterone (T; P < 0.05) in the fluid from medium-sized follicles, as well as in the content of all these steroids in the fluid from large-sized follicles (P < 0.001 for P 4 and P < 0.05 for A 4 and T). Denervation also caused a decrease in the content of A 4 (P < 0.01) and T (P < 0.001) in the wall of follicles. Neurectomy resulted in a significant increase in the immunoexpression of cholesterol side-chain cleavage cytochrome P450 in the follicles and a decrease of 3β-hydroxysteroid dehydrogenase. After denervation, plasma levels of LH, P 4 , A 4 , T, oestrone and oestradiol-17β were lower (P < 0.05-0.001) on the particular days of the study than in the control group. Our data revealed that the denervation of ovaries during the middle luteal phase of the oestrous cycle in gilts caused distinct changes in both the morphology and the steroidogenic activity of the organ, confirming an important role of the peripheral nervous system in the control of the gonad in this species. Acta Veterinaria Hungarica 55, 2007It is well known that mammalian ovaries are fairly innervated by fibres belonging to the adrenergic, cholinergic and/or peptidergic subsets of the autonomic and sensory systems. Ovarian function is thus regulated by both hormonal and neuronal input operating in concert to control follicular development, steroidogenesis and ovulation. Numerous studies performed on laboratory animals showed that the effects of gonad denervation are dependent not only on species and age of animals, but also on the experimental procedure. For instance, the blockade of ovarian innervation development in neonatal rats resulted in limited follicular growth, delayed puberty, decreased oestradiol-17β (E 2 ) secretion and marked irregularities of the oestrous cycles (Lara et al., 1990a). Conversely, chemical sympathectomy induced by guanethidine administration to newborn guinea pigs caused ovulation (Riboni et al., 1997). Although bilateral sectioning of the superior ovarian nerve (SON) in adult rats did not affect ovulation (Chávez et al., 1991), it was able to decrease the plasma levels of progesterone (P 4 ) and E 2 (Erskine and Weaver, 1988). On the other hand, an inhibition of this process occurred in adult guinea pigs exposed to guanethidine (Trujillo and Riboni, 2002). Moreover, it was indicated by Luna et al. ...