Can obestatin modulate the GnRH neurons activity?

Abstract

Obestatin, an anorexigenic peptide acting at the central nervous system and on the periperial level, can co-create neuroendocrine network, which modulate the gonadotrophic axis activity. The aim of this study was to investigate the role of intracerebroventricular obestatin infusion on the activity of the gonadoliberine (GnRH) neurons activity.The experiment was performed on peripubertal Polish Merino sheep (n=24). Animals were divided into 2 groups: control (Ringer-Lock solution infusions; n=12) and experimental (obestatin infusion, 25μl/120μl/h; n=12). Infusions were performed over three consecutive days; blood samples were collected on day 0 and day 3. After the experiment, the animals were slaughtered, and the chosen brain tissue was preserved for IHC and Real Time RT-qPCR analysis.It was also shown that exogenous obestatin changes the selected gene expression of GnRH pulse generator, decreases the secretory activity of GnRH neurons, resulting from the inhibition of GnRH release from median eminence terminal nerves, and also decreases the GnRH receptor gene expression in pituitary. On the basis of the obtained results it can be concluded that obestatin may be involved in the modulation of reproduction processes in animals at the level of the central nervous system. However, the mechanism of its action requires further research, especially identifying the obestatin receptor itself.