Neural regulation of the bovine corpus luteum

An in vitro study on noradrenergic modulation of final oocyte maturation in the catfish Heteropneustes fossilis

This study was aimed to elucidate in vitro the effects of endogenous catecholamines: dopamine (DA), noradrenaline (NA) and adrenaline (A), and the β-adrenergic blocker propranolol on induction of final oocyte maturation (FOM) in the catfish Heteropneustes fossilis. With this aim, post vitellogenic follicles from sexually mature gravid female catfish were incubated with each of DA, NA and A in a concentration range of 5-250 μM, and propranolol in a concentration range of 1-200 μg/mL at time points varying from 0 to 30 h). Translucent follicles without germinal vesicle (GV) and opaque follicles with GV were scored separately for the calculation of percentage germinal vesicle breakdown (GVBD), an index of FOM. Data were analyzed by one-way ANOVA and were considered statistically significant when P values were less than 0.05. The analysis of the data showed that the incubation with NA only stimulated GVBD in a concentration - and time-dependent manner. Though the incubation with propranolol decreased total follicular cAMP level significantly at and above 10 μg/mL concentrations, a significant effect of the GVBD increase was noticed at 50 μg/mL or higher. However, the 10 μg/mL concentration of propranolol was effective to inhibit the NA-induced GVBD significantly albeit at a low level (39%). The present study suggests that final oocyte maturation is modulated by NA through a β-adrenergic mechanism, implicating a neural control of oocyte maturation and ovulation in teleosts.

The role of adrenergic activation on murine luteal cell viability and progesterone production

Sympathetic innervations exist in mammalian CL. The action of catecholaminergic system on luteal cells has been the focus of a variety of studies. Norepinephrine (NE) increased progesterone secretion of cattle luteal cells by activating β-adrenoceptors. In this study, murine luteal cells were treated with NE and isoprenaline (ISO). We found that NE increased the viability of murine luteal cells and ISO decreased the viability of luteal cells. Both NE and ISO promoted the progesterone production. Nonselective β-adrenergic antagonist, propranolol reversed the effect of ISO on cell viability but did not reverse the effect of NE on cell viability. Propranolol blocked the influence of NE and ISO on progesterone production. These results reveal that the increase of luteal cell viability induced by NE is not dependent on β-adrenergic activation. α-Adrenergic activation possibly contributes to it. Both NE and ISO increased progesterone production through activating β-adrenergic receptor. Further study showed that CyclinD2 is involved in the increase of luteal cell induced by NE. 3β-Hydroxysteroid dehydrogenase, LHR, steroidogenic acute regulatory protein (StAR), and PGF2α contribute to the progesterone production induced by NE and ISO.

An in vitro study on catecholamine modulation of ovarian steroidogenic activity in the catfish Heteropneustes fossilis

In the present study, α-methylparatyrosine (α-MPT), a tyrosine hydroxylase inhibitor was used to impair ovarian catecholaminergic activity in vitro. The consequent effects on catecholamine (CA) levels were correlated with follicular steroid production. l-dihdroxyphenylalanine (l-DOPA, the precursor of CA) and human gonadotropin (hCG) were supplemented to reverse the effect of α-MPT. The experiments were conducted in two reproductive phases, namely preparatory and pre-spawning phases in female catfish Heteropneustes fossilis. The incubation with α-MPT inhibited ovarian l-DOPA, dopamine (DA), norepinephrine (NE) and epinephrine (EP) levels and the l-DOPA supplementation compensated the inhibitory effect. The level of tyramine (TR) was increased by the α-MPT treatment but inhibited by the l-DOPA supplementation. α-MPT produced stage-specific (seasonal) effects on ovarian estradiol-17β (E2); in the preparatory phase, E2 was decreased significantly at both 12 and 24h and in the pre-spawning phase, the level was stimulated over the respective control groups. The changes were higher at 24h in both phases. l-DOPA and hCG increased the E2 level significantly in the preparatory phase and reversed the inhibitory effect of α-MPT in the co-incubation groups. In the pre-spawning phase, α-MPT-stimulated the E2 level compared to the control groups, which was reversed by l-DOPA, hCG, or by both, in co-incubations. In contrast, the α-MPT treatment decreased progesterone (P4), 17-hydroxyprogesterone and 17,20β-dihydroxy-4-prenen-3-one (17,20β-DP) in a duration-dependent manner while the co-incubations with l-DOPA, hCG, or by both, significantly reversed the inhibitory effect. These results suggest that ovarian CAs (DA, NE and EP) may exert differential and stage-specific effects on E2, inhibition in the preparative phase and stimulation in the pre-spawning phase. The progestin steroids appear to be stimulated by CAs. In conclusion, this study highlights a possible direct/causal functional interaction between CA activity and gonadotropin on steroidogenic activity, and that CAs may be involved in regulating temporal secretion of the hormones through causing the shift in steroidogenic pattern.

The Noradrenergic Innervation and Steroidogenic Activity of Porcine Cystic Ovaries

The aim of the present study was to investigate the distribution and density of noradrenergic nerve fibres (NNFs), content of catecholamines (CATs) and steroids in the cystic ovaries of gilts receiving DXM from middle luteal phase. Cystic status of ovaries was induced by i.m. DXM injections on days 7-21 of the estrous cycle. During the same time, gilts in the control group received saline. The ovaries were collected on predicted day 11 of the second studied estrous cycle. The cystic ovaries were supplied by more numerous NNFs than the control gonads. Moreover after DXM injections, the content of CATs and progesterone and androstendione (A4) in the cystic wall were elevated, while the levels of A4, testosterone and estradiol-17β in the cystic fluid were lowered. Our results show that in the porcine cystic ovaries, induced by DXM injections from middle phase of estrous cycle, increased the density of NNFs and level of CATs, and that it was accompanied by changes in the content of steroids. Moreover, this study is a further confirmation that the morphological and functional changes of cystic ovaries are partly dependent on phase of the estrous cycle in which the induction of the ovarian cysts was initiated.

Effect of prolactin acting on the coeliac ganglion via the superior ovarian nerve on ovarian function in the postpartum lactating and non-lactating rat

Whether prolactin (PRL) has a luteotrophic or luteolytic effect in the rat ovary depends on the nature of the corpora lutea present in the ovaries and the hormonal environment to which they are exposed. The aim was to investigate the effect of PRL acting on the coeliac ganglion (CG) on the function of the corpora lutea on day 4 postpartum under either lactating or non-lactating conditions, using the CG-superior ovarian nerve-ovary system. The ovarian release of progesterone (P), estradiol, PGF2α, and nitrites was assessed in the ovarian compartment at different incubation times. Luteal mRNA expression of 3β-HSD, 20α-HSD, aromatase, PGF2α receptor, iNOS, Bcl-2, Bax, Fas and FasL was analysed in the corpus luteum of pregnancy at the end of the experiments. Comparative analysis of control groups showed that the ovarian release of P, nitrites, and PGF2α, the expression of PGF2α receptor, and the Bcl-2/Bax ratio were lower in non-lactating rats, with increased release of estradiol, and higher expression of aromatase, Fas and FasL, demonstrating the higher luteal functionality in ovaries of lactating animals. PRL added to the CG compartment increased the ovarian release of P, estradiol, nitrites and PGF2α, and decreased the Bcl-2/Bax ratio in non-lactating rats; yet, with the exception of a reduction in the release of nitrites, such parameters were not modified in lactating animals. Together, these data suggest that the CG is able to respond to the effect of PRL and, via a neural pathway, fine-tune the physiology of the ovary under different hormonal conditions.

Activity of Monoamine Oxidases in Rat Female Genital Organs During Preimplantation Period of Pregnancy

Our objectives in the present study were to determine the activity of monoamine oxidases A and B (MAO AB) in rat ovary, oviduct and uterus during preimplantation period of pregnancy. It should help us to clarify and better understand possible involvement of both MAO enzymes in the reproductive process. Pregnant females were killed employing a lethal dose of thiopental on the first (D1), on the third (D3), and on the fifth (D5) days of pregnancy. Rats were perfused transcardially with the PBS to rinse out of the body as much blood as possible. Ovaries, oviducts and uteri were immediately removed and stored until the measurement was done. MAO activity was determined by fluorescent monoamine oxidase detection kit. In the ovaries we have found the highest MAO activity at D3, followed by D1, and the lowest levels were recorded at D5 of pregnancy. In the oviducts, the highest MAO activity was detected again at D3, followed by D5, and by D1 of pregnancy. But statistical analysis did not reveal any difference between individual days of pregnancy nor in the ovaries, neither in uterine tubes. Uteri were the only organs, in which statistically significant differences were detected (p<0.001). The highest activity of MAO was observed at D5, followed by D1, and by D3 of pregnancy. Potential mechanisms responsible for the changed MAO activity in gonads during preimplantation period of pregnancy are proposed.

Impact of 2 doses of clorgyline on the rat preimplantation embryo development and the monoamine levels in urine

We have evaluated the impact of chronic administration of clorgyline, a potent monoamine oxidase A inhibitor and a former antidepressant, on the preimplantation embryo development in Wistar rats. Females were injected intraperitoneally daily for 30 days with saline (control animals), or with a low-dose clorgyline (LDC, 0.1 mg/kg per d) or with a high-dose clorgyline (HDC, 1 mg/kg per d). Embryos were isolated on day 5 of pregnancy and urine was collected by puncture of the urinary bladder. The number of embryos per female did not differ between experimental groups and control, but we have recorded a decreased number of embryos in HDC group compared to LDC (P < .05). We have found that LDC significantly reduced the presence of healthy embryos and increased the presence of the degenerated embryos (P < .001). The administration of the LDC resulted in the lowest cell number in blastocysts. We have observed significantly increased serotonin levels in HDC group compared to both control (P < .05) and LDC animals (P < .01). Norepinephrine (NE) levels in both experimental groups were significantly elevated compared to controls. Dopamine levels did not differ between groups (P > .05). We speculate that lesser negative effect of HDC compared to LDC on the preimplantation embryo development could be the consequence of the lower NE levels and/or elevated serotonin levels. Potential mechanisms mediating clorgyline-induced impaired preimplantation embryo development are proposed.

Long-term estradiol-17β administration decreases the number of neurons in the caudal mesenteric ganglion innervating the ovary in sexually mature gilts

The effect of estradiol-17β (E(2)) on the number and distribution of neurons in the caudal mesenteric ganglion (CaMG) supplying the ovary of adult pigs was investigated. Also, the numbers of ovarian dopamine-β-hydroxylase (DβH-), neuropeptide Y (NPY-), somatostatin (SOM-), galanin (GAL-) and estrogen receptor (ER)-immunoreactive perikarya as well as the density of the intraganglionic nerve fibers containing DβH and/or NPY, SOM, GAL were determined. E(2) was administered i.m. from day 4 of the first studied estrous cycle to the expected day 20 of the second studied cycle. Injections of E(2) (1) increased the E(2) level in the peripheral blood approximately 4-5 fold, (2) decreased the number of small-sized Fast Blue-positive postganglionic neurons in the CaMG, (3) decreased the number of small perikarya in the ventral, dorsal and central regions of the CaMG, (4) decreased the number of large perikarya in the dorsal and central regions, (5) decreased the number of small and large perikarya in the CaMG that were DβH(+)/NPY(+), (6) decreased the number of small DβH(+) but NPY(-) perikarya, (7) decreased the number of small perikarya coded DβH(+)/SOM(+) and DβH(+)/SOM(-), (8) decreased the number of small DβH(+)/GAL(-) perikarya, (9) decreased the number of small and large perikarya expressing ER subtypes α and β and (10) decreased the total number of nerve fibers in the CaMG containing DβH and/or NPY and DβH and/or GAL. These results show that long-term E(2) treatment of adult gilts downregulates the populations of both noradrenergic and ERs expressing ovarian neurons in the CaMG. Our findings suggest also that elevated E(2) levels that occur during pathological states may regulate gonadal function(s) by affecting ovary supplying neurons.

Temporal and periovulatory changes in ovarian catecholamines in the catfish Heteropneustes fossilis

A high performance liquid chromatography-fluorescence detection method was employed to demonstrate temporal and periovulatory changes in ovarian catecholamines in the catfish Heteropneustes fossilis. Tyrosine, L-DOPA, dopamine (DA), norepinephrine (NE) and epinephrine showed significant seasonal and diurnal changes during the reproductive cycle. A high concentration of tyrosine was detected, the values increased in day and decreased in night during recrudescence from preparatory to spawning phases. Similarly, L-DOPA increased during the breeding phase giving the day value concentration peak in the spawning phase and the night value peak in the postspawning phase. DA activity or turnover index (calculated as a ratio of DA to 3,4-dihydroxyphenylacetic acid, DOPAC) showed a bimodal pattern with the major activity peak in the postspawning phase and the minor one in the prespawning phase, the spawning phase registered the lowest activity. NE activity or turnover index (ratio of NE to normetanephrine, NME) increased during the recrudescent phase to give the peak in the spawning phase and decreased in the quiescent phase. Epinephrine elicited an inverse relationship in the day-night pattern, the day values increased to the peak in the spawning phase. All the study correlates showed significant periovulatory changes after hCG treatment. DA activity dropped to the nadir at 8h but recovered at 16 and 24h. NE activity showed only a marginal decrease up to 16h but decreased drastically at 24h. Epinephrine levels remained unchanged but only to increase at 24h. The seasonal patterns and periovulatory changes strongly point to important functions for catecholamines in the ovary. The occurrence of tyramine (an invertebrate neurotransmitter) suggests the presence of alternate catecholamine pathway in fish ovary.

Annual and periovulatory changes in tyrosine hydroxylase activity in the ovary of the catfish Heteropneustes fossilis

In the present study, tyrosine hydroxylase (TH, the rate-limiting enzyme in catecholamine synthesis) activity was demonstrated in the ovary of the catfish to elucidate the possible physiological role of catecholamines in the gonad. The ovary is innervated by seven pairs of nerves, originating from the paired sympathetic chain lying dorsal to the posterior kidney. Ovarian TH activity showed a significant annual variation (P<0.001, one-way ANOVA), correlating with gonado-somatic index. Activity was low from December to February (resting phase), increased from March to July (recrudescent phase) and then decreased in post-spawning phase (August-November). The annual pattern was similar to that of the brain. An intraperitoneal injection of 100 IU hCG/fish induced significant periovulatory changes in TH activity with the peak rise at 16 h, and the activity decreased after egg-stripping (P<0.001, one-way ANOVA). Brain TH activity showed similar periovulatory changes. The results suggest that catecholamine synthesis is increased during both ovarian recrudescence and spawning of the annual reproductive cycle, implying a functional role in ovarian growth, maturation and ovulation.

Androgen receptors in coeliac ganglion in late pregnant rat

The ovarian function is controlled by endocrine factors and neural influence. In late pregnant rat, androstenedione, from the coeliac ganglion, has a luteotrophic effect in the ex vivo coeliac ganglion-superior ovarian nerve-ovary system. In this work we investigate the presence of androgen receptors in the coeliac ganglion of late pregnant rats by immunohistochemistry. We also explore, from a physiological point of view, the potential participation of these receptors in the androstenedione ganglionic action on progesterone release and metabolism, as well as on nitrites release in the ovary compartment. The coeliac ganglion was isolated after being fixed in situ and immunohistochemistry was performed. In the system, three experimental groups were used with the addition of (a) androstenedione, (b) flutamide, and (c) androstenedione plus flutamide in the ganglion compartment. Progesterone and nitrite concentrations were determined in the ovary compartment at different incubation times. Corpora lutea samples isolated at the end of incubation were used to determine the expressions and activities of the progesterone synthesis (3beta-hydroxysteroid-dehydrogenase, 3beta-HSD) and degradation (20alpha-hydroxysteroid-dehydrogenase, 20alpha-HSD) enzymes. Immunohistochemistry revealed cytoplasmatic androgen receptor immunoreactivity in neural somas in the coeliac ganglion. In the coeliac ganglion-superior ovarian nerve-ovary system, androstenedione addition increased 3beta-HSD and decreased 20alpha-HSD, showed a tendency to decrease 20alpha-HSD expression, and increased nitrites release in relation to control. Androstenedione plus flutamide decreased progesterone and nitrites release in relation to the androstenedione group. This work demonstrates the presence of androgen receptors in neurons of celiac ganglion and provides evidence for the luteotrophic action of androstenedione via a neural pathway that may be mediated by these receptors.

Perceived racial discrimination and risk of uterine leiomyomata

BACKGROUND

The incidence of uterine leiomyomata (fibroids, myomas) is 2-3 times higher in black women than white women. Black women also report higher levels of racial discrimination. We evaluated the hypothesis that greater exposure to racism increases myoma risk in black women.

METHODS

Data were derived from the Black Women's Health Study, a prospective cohort study of US black women age 21-69 years in 1995. In 1997, women reported on "everyday" and "lifetime" experiences of racism. From 1997 through 2003, we followed 22,002 premenopausal women to assess the association between self-reported racism and risk of myomas. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were estimated from Cox regression models.

RESULTS

During 107,127 person-years of follow-up, 3440 new cases of uterine myomas confirmed by ultrasound (n = 2774) or surgery (n = 666) were reported. All IRRs for "lifetime" and "everyday" experiences of racism were above 1.0. Using a summary variable that averaged the responses from 5 "everyday" racism items, multivariable IRRs comparing quartiles 2, 3, and 4 to quintile 1 (lowest) were 1.16 (95% CI = 1.04-1.29), 1.19 (1.06-1.32), and 1.27 (1.14-1.43), respectively. Multivariable IRRs comparing women who reported 1, 2, or 3 lifetime occurrences of major discrimination (ie, job, housing, or police) relative to those who reported none were 1.04 (0.96-1.13), 1.17 (1.07-1.28), and 1.24 (1.10-1.39), respectively. Results did not vary according to case definition (ultrasound vs. surgery) or health care utilization. Associations were weaker among foreign-born women and among women with higher coping skills.

CONCLUSIONS

Perceived racism was associated with an increased risk of uterine myomas in US-born black women.

Dopamine receptor repertoire of human granulosa cells

BACKGROUND

High levels of dopamine (DA) were described in human ovary and recently evidence for DA receptors in granulosa and luteal cells has been provided, as well. However, neither the full repertoire of ovarian receptors for DA, nor their specific role, is established. Human granulosa cells (GCs) derived from women undergoing in vitro fertilization (IVF) are an adequate model for endocrine cells of the follicle and the corpus luteum and were therefore employed in an attempt to decipher their DA receptor repertoire and functionality.

METHODS

Cells were obtained from patients undergoing IVF and examined using cDNA-array, RT-PCR, Western blotting and immunocytochemistry. In addition, calcium measurements (with FLUO-4) were employed. Expression of two DA receptors was also examined by in-situ hybridization in rat ovary. Effects of DA on cell viability and cell volume were studied by using an ATP assay and an electronic cell counter system.

RESULTS

We found members of the two DA receptor families (D1- and D2 -like) associated with different signaling pathways in human GCs, namely D1 (as expected) and D5 (both are Gs coupled and linked to cAMP increase) and D2, D4 (Gi/Gq coupled and linked to IP3/DAG). D3 was not found. The presence of the trophic hormone hCG (10 IU/ml) in the culture medium for several days did not alter mRNA (semiquantitative RT-PCR) or protein levels (immunocytochemistry/Western blotting) of D1,2,4,5 DA receptors. Expression of prototype receptors for the two families, D1 and D2, was furthermore shown in rat granulosa and luteal cells by in situ hybridization. Among the DA receptors found in human GCs, D2 expression was marked both at mRNA and protein levels and it was therefore further studied. Results of additional RT-PCR and Western blots showed two splice variants (D2L, D2S). Irrespective of these variants, D2 proved to be functional, as DA raised intracellular calcium levels. This calcium mobilizing effect of DA was observed in the absence of extracellular calcium and was abolished by a D2 blocker (L-741,626). DA treatment (48 h) of human GCs resulted in slightly, but significantly enlarged, viable cells.

CONCLUSION

A previous study showed D2 in human GCs, which are linked to cAMP, and the present study reveals the full spectrum of DA receptors present in these endocrine cells, which also includes D2-like receptors, linked to calcium. Ovarian DA can act thus via D1,2,4,5, which are co-expressed by endocrine cells of the follicle and the corpus luteum and are linked to different signaling pathways. This suggests a complex role of DA in the regulation of ovarian processes.

Involvement of the coeliac ganglion in the luteotrophic effect of androstenedione in late pregnant rats

Using the ex vivo coeliac ganglion-superior ovarian nerve-ovary system at the end of pregnancy when luteal regression starts, we investigated whether, when administered systemically or when added directly to the ganglion compartment, androstenedione (A2) can reverse such regression, and whether the neural (noradrenaline (NA)) and endocrine (A2) joint action modifies the release of ovarian progesterone. The experimental groups were as follows: group 1 – A2 injected systemically 48 h before incubation of the system (A2)s; group 2 – A2 directly added to the ganglion compartment (A2)g; group 3 – A2 injected 48 h before incubation of the system with NA in the ganglion compartment (A2 + NA); group 4 – A2 plus NA added to the ganglion compartment (NA + A2)g. The controls were ex vivo systems without treatment (control), and with the addition of NA alone in the ganglion compartment (NA). The results were as follows. For (A2)s versus control, progesterone increased on days 19 and 21 of pregnancy at all the studied times and only at 180 min on day 20. For (A2 + NA) versus (A2)s, progesterone increased on days 19 and 21. For (A2 + NA) versus NA, progesterone increased at all the studied times on days 19 and 21 and at 180 min on day 20. For (A2)g versus control, progesterone significantly increased every pregnancy day. For (NA + A2)g versus (A2)g, progesterone decreased at 120 and 180 min on day 19. For (NA + A2)g versus NA, progesterone increased on days 20 and 21. We can conclude that A2 can reverse the functional regression of the corpus luteum either systemically or, what is more surprising, when directly added to the coeliac ganglion, whose action on the ovary is exerted via superior ovarian nerve.

Stimulatory effect of LH, PGE2 and progesterone on StAR protein, cytochrome P450 cholesterol side chain cleavage and 3beta hydroxysteroid dehydrogenase gene expression in bovine luteal cells

The aim of these studies was to investigate the effect of LH, progesterone (P4), PGE, noradrenaline (NA) and a nitric oxide donor, S-nitroso-N-acetylpenicillamine (S-NAP), on steroid acute regulatory protein (StAR), 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and cytochrome P450 side chain cleavage (P450scc) gene expression and on the synthesis of their protein products. Bovine luteal cells were collected and prepared on days 6-10 of the estrous cycle and preincubated in vitro for 24 h. Thereafter, medium was changed and supplemented with one of six treatments: control medium, LH (100 ng/ml), P4 (10(-5)M), PGE2 (10(-6)M), NA (10(-5)M) or S-NAP (10(-4)M). In Experiment 1, luteal cells (10(6)/well) were incubated for 3, 6, 18 and 24 h. After incubation, total RNA was isolated and P4 concentrations in medium was determined. Semiquantitative RT-PCR was used to measure gene expression. In Experiment 2, luteal cells were preincubated for 24h, then stimulated as in Experiment 1. Total protein was isolated from lysed cells and Western blot analysis was performed using specific antibodies against the StAR, 3beta-HSD and cytochrome P450scc proteins. Bands were analyzed by means of KODAK 1D Image Analysis Software. In Experiment 1, LH and PGE2 stimulated secretion of progesterone from luteal cells. Concentrations of mRNA for StAR, 3beta-HSD, cytochrome P450scc were increased after 6 h in cells stimulated with LH, PGE2 and P4 (P<0.05). Gene expression was not affected by NA. In Experiment 2, LH, P4 and PGE2 induced an increase in the concentration of these three proteins. S-NAP inhibited both concentrations of mRNA and protein for StAR, 3beta-HSD, cytochrome P450scc. Therefore, the increase in secretion of P4 induced by LH and PGE2 is associated with increases in StAR, 3beta-HSD and cytochrome P450scc gene expression. This genomic response may be mediated in part through a positive effect of P4 on the expression of these genes observed in this experiment.

alpha1-Adrenergic receptor in rat ovary: presence and localization

Noradrenaline modulates ovarian steroidogenesis, stimulates ovulation, and probably promotes follicular development in the ovary. It has been suggested that these effects of noradrenaline are mediated by alpha- and/or beta-adrenergic receptors (ARs) in the ovary. The purpose of the present study was to examine whether alpha(1)-AR is present in the rat ovary. In Western blotting, antibody against alpha(1)-ARs recognized a major protein in the ovary of adult (10-week-old) rats with a molecular weight of 80 kDa, which is similar to that of the alpha(1B)-AR subtype. Immunohistochemistry using this antibody showed that alpha(1)-AR was detected at various sites in the ovary, including large antral follicle, germinal epithelium at the circumference of large antral follicle, corpus luteum, and interstitial tissue. These results confirm that the ovary contains alpha(1)-AR (probably alpha(1B)-subtype), and suggest that this receptor mediates some of the activities of noradrenaline in the regulation of ovarian functions. Furthermore, we found that alpha(1)-AR is present in oocyte of large antral follicle, suggesting that noradrenaline acts on oocyte via this receptor.

Dexamethasone-induced Changes in Sympathetic Innervation of Porcine Ovaries and in Their Steroidogenic Activity

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 P450(scc) and 3beta-HSD in the cysts, a significant increase of P450(scc) in the follicles, and a decrease of 3beta-HSD and P450(arom). 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.