Effect of peripheral neural stimulation with allopregnanolone on ovarian physiology.

Neuroactive steroids can rapidly regulate multiple physiological functions on the central and peripheral nervous systems. The aims of the present study were to determine whether allopregnanolone (ALLO), administered in a low nanomolar and a high micromolar concentrations, can: a) induce changes in the ovarian progesterone (P4) and estradiol (E2) release, b) modify the ovarian mRNA expression of 3 β-HSD, 20 α-HSD and 3 α-HSD, c) modulate the ovarian expression of progesterone receptors A and B, α and β estrogenic receptors, LH receptor (LHR) and FSH receptor (FSHR). To further characterize ALLO peripheral actions, the effects were evaluated using a superior mesenteric ganglion-ovarian nervous plexus-ovary (SMG-ONP-O) and a denervated ovary (DO) systems. ALLO SMG administration increased P4 concentration in the incubation liquid, by decreasing ovarian 20α-HSD mRNA, it also increased ovarian 3α-HSOR mRNA expression. In addition, ALLO neural peripheral modulation induced an increase in the expression of ovarian LHR, PRA, PRB, and ERα. Direct ALLO administration to the DO decreased E2 and increased P4 concentration in the incubation liquid. The mRNA expression of 3β-HSD decreased, and 20α-HSD increased. Further, ALLO in the OD significantly changed ovarian FSHR, and PRA expression. This is the first evidence of ALLO direct effect on ovarian steroidogenesis. Our results provide important insights about how this neuroactive steroid interacts both with the PNS and the ovary, these findings might help devise some of the pleiotropic effects of neuroactive steroids on female reproduction. Moreover, ALLO modulation of ovarian physiology might help uncover novel treatment approaches for reproductive diseases.