[show abstract][hide abstract] ABSTRACT: Transforming growth factor β1 (TGF-β1) is a pleiotropic cytokine that modulates cell homeostasis. In Leydig cells, TGF-β1 exerts stimulatory and inhibitory effect depending on the type I receptor involved in the signaling pathway. The aim of the present work was to study the signaling mechanisms and the intermediates involved in the action of TGF-β1 on TM3 Leydig cell proliferation in the presence or absence of progesterone. The MTT assay showed that the presence of progesterone in the culture media lead to a proliferative effect that was blocked by Ru 486, an inhibitor of progesterone receptor; and ALK-5 did not participate in this effect. TGF-β1 (1ng/ml) increased the expression of p15 (an inhibitor of cell cycle) in TM3 Leydig cells, and this effect was blocked by progesterone (1μM). The expression of PCNA presented a higher increase in the cell cultured with TGF-β1 plus progesterone than in cells cultured only with TGF-β1. Progesterone induced the gene expression of endoglin, a cofactor of TGF-β1 receptor that leads to a stimulatory signaling pathway, despite of the absence of progesterone response element in endoglin gene. In addition, the presence of progesterone induced the gene expression of egr-1 and also KLF14, indicating that this steroid channels the signaling pathway into a non-canonical mechanism. In conclusion, these findings suggest that the proliferative action of TGF-β1 involves endoglin. This co-receptor might be induced by KLF14 which is probably activated by progesterone.
[show abstract][hide abstract] ABSTRACT: 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.
General and Comparative Endocrinology 01/2013; · 2.82 Impact Factor
[show abstract][hide abstract] ABSTRACT: There is evidence suggesting that estradiol (E(2)) regulates the physiology of the ovary and the sympathetic neurons associated with the reproductive function. The objective of this study was to investigate the effect of E(2) on the function of late pregnant rat ovaries, acting either directly on the ovarian tissue or indirectly via the superior ovarian nerve (SON) from the celiac ganglion (CG). We used in vitro ovary (OV) or ex vivo CG-SON-OV incubation systems from day 21 pregnant rats. Various concentrations of E(2 )were added to the incubation media of either the OV alone or the ganglion compartment of the CG-SON-OV system. In both experimental schemes, we measured the concentration of progesterone in the OV incubation media by radioimmunoassay at different times. Luteal messenger RNA (mRNA) expression of 3β-hydroxysteroid dehydrogenase (3β-HSD) and 20α-hydroxysteroid dehydrogenase (20α-HSD) enzymes, respectively, involved in progesterone synthesis and catabolism, and of antiapoptotic B-cell lymphoma 2 (Bcl-2) and proapoptotic Bcl-2-associated X protein (Bax), were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) at the end of the incubation period. Estradiol added directly to the OV incubation or to the CG of the CG-SON-OV system caused a decline in the concentration of progesterone accumulated in the incubation media. In addition, E(2), when added to the OV incubation, decreased the expression of 3β-HSD and the ratio of Bcl-2/Bax. We conclude that through a direct effect on the OV, E(2) favors luteal regression at the end of pregnancy in rats, in association with neural modulation from the CG via the SON.
[show abstract][hide abstract] ABSTRACT: Androstenedione can affect luteal function via a neural pathway in the late pregnant rat. Here, we investigate whether androstenedione is capable of opposing to regression of pregnancy corpus luteum that occurs after parturition, indirectly, from the coeliac ganglion. Thus, androstenedione was added into the ganglionar compartment of an ex vivo coeliac ganglion-superior ovarian nerve-ovary system isolated from non-lactating rats on day 4 postpartum. At the end of incubation, we measured the abundance of progesterone, androstenedione and oestradiol released into the ovarian compartment. Luteal mRNA expression and activity of progesterone synthesis and degradation enzymes, 3β-hydroxysteroid-dehydrogenase (3β-HSD) and 20α-hydroxysteroid-dehydrogenase (20α-HSD), respectively, as well as the aromatase, Bcl-2, Bax, Fas and FasL transcript levels, were also determined. Additionally, we measured the ovarian release of norepinephrine, nitric oxide and luteal inducible nitric oxide synthase (iNOS) mRNA expression. The presence of androstenedione in the ganglion compartment significantly increased the release of ovarian progesterone, androstenedione and oestradiol without modifying 3β-HSD and 20α-HSD activities or mRNA expression. The ovarian release of oestradiol in response to the presence of androstenedione in the ganglion compartment declined with time of incubation in accord with a reduction in the aromatase mRNA expression. Androstenedione added to the ganglion compartment decreased FasL mRNA expression, without affecting luteal Bcl-2, Bax and Fas transcript levels; also increased the release of norepinephrine, decreased the release of nitric oxide and increased iNOS mRNA. In summary, on day 4 after parturition, androstenedione can mediate a luteotropic effect acting at the coeliac ganglion and transmitting to the ovary a signaling via a neural pathway in association with increased release of norepinephrine, decreased nitric oxide release, and decreased expression of FasL.
The Journal of steroid biochemistry and molecular biology 03/2011; 125(3-5):243-50. · 2.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: 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.
[show abstract][hide abstract] ABSTRACT: Both peripheral innervation and nitric oxide (NO) participate in ovarian steroidogenesis. Considering the existence of the nitric oxide/ nitric oxide synthase system in the peripheral neural system and in the ovary, the aim of this work was to analyze if the liberation of NO in the ovarian compartment of prepubertal rats is of ovarian and/or ganglionic origin. The analysis is carried out from a physiological point of view using the experimental coeliac ganglion--Superior Ovarian Nerve--ovary model with and without ganglionic cholinergic stimulus Acetylcholine (Ach) 10(-6) M. Non selective and selective inhibitors of the synthase nitric oxide enzyme were added to the ovarian and ganglionic compartment, and the liberation of nitrites (soluble metabolite of the nitric oxide) in the ovarian incubation liquid was measured. We found that the non-selective inhibitor L-nitro-arginina methyl ester (L-NAME) in the ovarian compartment decreased the liberation of nitrites, and that Aminoguanidine (AG) in two concentrations in a non-dose dependent form provoked the same effect. The addition of Ach in ganglion magnified the effect of the inhibitors of the NOS enzyme. The most relevant results after the addition of inhibitors in ganglion were obtained with AG 400 and 800 microM. The inhibition was made evident with and without the joint action of Ach in ganglion. These data suggest that the greatest production of NO in the ovarian compartment comes from the ovary, mainly the iNOS isoform, though the coeliac ganglion also contributes through the superior ovarian nerve but with less quantity.