Evidence that Melatonin Increases Inhibin Beta-A and Follistatin Gene Expression in Ovaries of Pinealectomized Rats

Melatonin plays an important role in the regulation of ovarian function including oocyte maturation in different mammalian species. Many studies indicate that melatonin has an impact on the ovarian function of a variety of ovarian cells. However, the information on the exact mechanism and involved hormones is low. To evaluate inhibin beta-A (INHBA) and follistatin (FST) expression in the ovaries of pinealectomized rats treated with melatonin, thirty adult female Wistar rats were randomized into three groups of ten animals each: group 1 (GSh), sham-operated controls receiving vehicle; group 2 (GPx), pinealectomized animals receiving vehicle; and group 3 (GPxMe), pinealectomized animals receiving replacement melatonin (1.0 mg/kg body weight. It was assumed that each animal drank 6.5 ± 1.2 ml per night and weighs approximately 300 g.) for 60 consecutive days. The ovaries were collected for mRNA abundance and protein of INHBA and FST by qRT-PCR and immunohistochemical analyses, respectively. Treatment with melatonin resulted in the upregulation of INHBA and FST genes in the ovarian tissue of the melatonin-treated animals (GPxMe), when compared with GPx. These findings were then confirmed by analyzing the expression of protein by immunohistochemical analyses, which revealed higher immunoreactivity of INHBA and FST in GPxMe animals in the follicular cells compared with GSh and GPx rats. Melatonin increases the expression of INHBA and FST in the ovaries of pinealectomized female rats.