Neuromodulatory effect of oestradiol in the metabolism of ovarian progesterone and oestradiol during dioestrus II: participation of the superior mesenteric ganglion

Abstract

The aims of the present study were to determine: (1) whether oestradiol (E) in the superior mesenteric ganglion (SMG) modifies the release of ovarian progesterone (P), androstenedione (A) and E, the activity and gene expression of 3β-hydroxysteroid dehydrogenase (3β-HSD) and 20α-HSD and the expression of P450 aromatase (Cyp19a1) and (2) whether any such modifications are related to changes in ovarian nitric oxide (NO) and noradrenaline (NA) levels during dioestrus II. Using an ex vivo SMG-ovarian nervous plexus-ovary system, ovarian P release was measured following the addition E plus tamoxifen (Txf) (10M) to the ganglion, whereas A, E, NA and NO were measured following the addition of E alone. Steroids were measured by radioimmunoassay, NA concentrations were determined by HPLC and gene expression was evaluated using reverse transcription-polymerase chain reaction. Oestradiol in the ganglion decreased ovarian P, E and NA release, as well as 3β-HSD activity, but increased the release of A and nitrites, as well as the 20α-HSD expression and its activity. No changes were observed in Cyp19a1 gene expression. The addition of E plus Txf to the ganglion reversed the effects of E alone. The action of oestradiol in SMG favours the beginning of functional luteolysis, due to an increase in NO release and a decrease in NA in the ovary. These results may help elucidate the role of E in hormone-dependent pathologies in women.

Superior mesenteric ganglion neural modulation of ovarian angiogenesis, apoptosis and proliferation by the neuroactive steroid allopregnanolone

“…Some of the known effects of NA in the ovary are steroidogenesis modulation, 83,129,130 ovulation, 131 promotion of follicle development 132,133 and corpora lutea function. 63 Alterations in the ovarian noradrenergic modulation thus have important effects in ovarian physiology and might mediate some of the the effects of ALLO.…”

“…Indeed, endogenous GABA can inhibit the release of NA in stimulated ovarian sympathetic nerve fibers, 128 and could be responsible for the effects of ALLO. Some of the known effects of NA in the ovary are steroidogenesis modulation, 83,129,130 ovulation, 131 promotion of follicle development 132,133 and corpora lutea function 63 . Alterations in the ovarian noradrenergic modulation thus have important effects in ovarian physiology and might mediate some of the the effects of ALLO.…”

“…The OPN innervates the ovarian bursa, ovary and oviduct, 60,61 the axons that accompany the ovarian artery penetrate through the hilum and innervate the ovarian medulla and cortex. The principal neurotransmitters are noradrenaline (NA), nitric oxide (NO), substance P (SP) and neuropeptide Y 62‐64 …”

“…The principal neurotransmitters are noradrenaline (NA), nitric oxide (NO), substance P (SP) and neuropeptide Y. [62][63][64] There is evidence of the existence of GABAergic neurons and GABAergic signaling in the sympathetic ganglia that innervates the ovary. [65][66][67] In addition, the mammalian ovary expresses a wide variety of receptors for neurotransmitters, such as NA, 68 acetylcholine 69 and GABA, 70 amongst others, which have distinct functions on ovarian structures.…”