Secretion of steroid hormones by the ovaries is regulated by hormonal and neural signals. In the rat, the right and left ovaries’ ability to secrete steroid hormones is different and varies throughout the estrous cycle. Gonadotropins stimulate the synthesis of 3β and 17β hydroxysteroid dehydrogenase and aromatase by activating the expression of genes codifying for each hormone. The aim of the present study was to analyze if the expression of genes codifying for 3β-HSD, 17β-HSD and aromatase in the ovaries varies along the estrous cycle, and its dependence of superior ovarian nerve innervation. At 07.00 h on each day of the estrous cycle, adult cyclic rats were submitted to the unilateral section of the superior ovarian nerve (SON) or kept as control. The animals were killed one hour after surgery. Progesterone, testosterone and estradiol serum levels varies depending the day of the cycle and the SON sectioned. The expression of the genes codifying for each enzyme also varies along the estrous cycle, depending on the ovary studied the day of the cycle and the SON sectioned. The results suggest that the expression of genes codifying for three key enzymes in ovarian steroidogenesis is regulated, among other signals, by those arriving through the ovarian innervations and that such regulation varies along the estrous cycle.
Nora Hilda Rosas¹, Marta L Santiago², Adriana Zárate², Mariluz Angulo Parra¹, Angélica Flores², Sara E Cruz-Morales³, and Roberto Dominguez²*