Fig. (2).

A schematic view of the interplay between the HPG and gut-brain axis. Kisspeptin neurons convey to GnRH neurons a plethora of central and peripheral metabolic signals. Orexigenic and anorexigenic peptides influence kisspeptin neurons with stimulatory or inhibitory effects, respectively. In addition, peripheral hormones such as leptin and ghrelin, coming from adipose tissue and gut, respectively, via kisspeptin neurons, inform the HPG axis of metabolic reserves of the body. As final effect, in both sexes, the reproductive activity may be stimulated or inhibited.