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

Abstract

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 (A 2 ) can reverse such regression, and whether the neural (noradrenaline (NA)) and endocrine (A 2 ) joint action modifies the release of ovarian progesterone. The experimental groups were as follows: group 1 -A 2 injected systemically 48 h before incubation of the system (A 2 ) s ; group 2 -A 2 directly added to the ganglion compartment (A 2 ) g ; group 3 -A 2 injected 48 h before incubation of the system with NA in the ganglion compartment (A 2 1 NA); group 4 -A 2 plus NA added to the ganglion compartment (NA 1 A 2 ) 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 (A 2 ) 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 (A 2 1 NA) versus (A 2 ) s , progesterone increased on days 19 and 21. For (A 2 1 NA) versus NA, progesterone increased at all the studied times on days 19 and 21 and at 180 min on day 20. For (A 2 ) g versus control, progesterone significantly increased every pregnancy day. For (NA 1 A 2 ) g versus (A 2 ) g , progesterone decreased at 120 and 180 min on day 19. For (NA 1 A 2 ) g versus NA, progesterone increased on days 20 and 21. We can conclude that A 2 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.

Pregnancy in rats is modulated by ganglionic cholinergic action

“…The luteotropic effect of androstenedione has been widely demonstrated in different experimental schemes (Carrizo et al 1994, Hillier et al 1994, Thordarson et al 1997, Goyeneche et al 2002 and even in the celiac ganglion-SON-ovary via SON (Casais et al 2006). Our results indicate that the ganglionic cholinergic action, mainly on the liberation of androstenedione, would act favoring the luteal regression occurring at the end of gestation which is necessary for the delivery to occur.…”

“…Their synthesis is regulated by the hypophysial gonadotropins and modulated by placental factors (Rothchild 1981) among others (Villavicencio et al 2002) and the neural effect mainly caused by the superior ovarian nerve (SON) (Lawrence & Burden 1980, D'Albora et al 2000, Aguado 2002. Using different experimental schemes, we have demonstrated that the SON modifies the liberation of ovarian steroids in different stages of life in rats (De Bortoli et al 2000, Sosa et al 2000, Casais et al 2001, 2006, Forneris & Aguado 2002. Fibers from the SON directly innervate the theca and secondary interstitial cells and they exert an indirect action on the corpus luteum (Erickson et al 1985).…”

Androstenedione acts on the coeliac ganglion and modulates luteal function via the superior ovarian nerve in the postpartum rat

“…We have shown that under our experimental ex vivo conditions the SON releases catecholamines and nitric oxide to the ovarian compartment [6,14,16]. It has been shown that the CG expresses the enzyme tyrosine hydroxylase that controls the synthesis of norepinephrine [30].…”

“…We have provided evidence that systemic administration of androstenedione or its addition to the ganglion compartment of the CG-SON-ovary system, opposes to the functional regression of the corpora lutea at the end of pregnancy in rats [14][15][16]. We further demonstrated that androgen receptor immunoreactive proteins are present in the neurons of the CG before parturition, suggesting that the indirect luteotropic activity of androstenedione may be mediated by these receptors and that they can eventually modulate the synthesis of neurotransmitters by the SON [6].…”

“…Our laboratory has demonstrated that in addition to the mainstream hormonal regulators such as oestradiol and prolactin, the physiology of the rat corpus luteum of pregnancy is modulated by the peripheral nervous system [6,[14][15][16][17].…”