Allopregnanolone modulates the 3E-hidroxiesteroide dehydrogenase in hypothalamus and ovary

VEGA OROZCO, A.; LACONI M.; CHAVEZ, C.; GIULIANI F.; SOSA Z.; CABRERA R.

HORMONE AND METABOLIC RESEARCH

GEORG THIEME VERLAG KG

Lugar: Thieme Publishers; Año: 2014

0018-5043

The aim of this work was to determine whether i.c.v administration of allopregnanolone modifies the 29 ȕ-hydroxysteroid dehydrogenase (3ȕ-HSD) enzymatic activity and gene expression in the 30 hypothalamus and the ovary of in vivo and ex vivo systems on proestrus (PE) and dioestrus I (DI) day. 31 Experimental groups were injected with allopregnanolone, bicuculline and bicuculline plus 32 allopregnanolone. In the in vivo experiment, the animals were decapitated; the hypothalamus and the 33 ovaries were removed thirty minutes after the i.c.v injections. In the ex vivo experiment, the Superior 34 Mesenteric Ganglion-Ovarian Nerve Plexus-ovary system was immediately extracted and incubated in a 35 Krebs Ringer buffer at 37 ºC in a metabolic bath, after the i.c.v injection. The ovarian compartment 36 fluid was separated to determine progesterone by radioimmunoanalysis. Results indicate that 37 allopregnanolone causes a decrease in the hypothalamic and ovarian 3ȕ-HSD enzymatic activity during 38 PE in in vivo experiments. However, no changes are observed in gene expression. Allopregnanolone did 39 neither modify the hypothalamic 3ȕ-HSD activity, nor the gene expression during DI, but it did increase 40 in the ovary. Ovarian 3ȕ-HSD activity increased in both stages with the ex vivo SMG-ONP-Ovary 41 system, but gene expression increased only during DI, which was reversed by an i.c.v injection of 42 bicuculline. P 4 increased in the ovarian incubation liquid in both stages, with different release profiles. 43 The i.c.v administration of allopregnanolone through the GABAergic system modulated 3ȕ-HSD 44 activity and gene expression by modifying both the neuroendocrine axis and the neural control of 45 ovarian steroidogenesis through the peripheral nervous system in a time- and cycle-dependent manner.