The role of neonatal kisspeptin in long-term social behavior in mammals.

Kisspeptins (Kiss) are key regulators of the hypothalamic-pituitary-gonadal axis, influencing testosterone surges essential for brain masculinization and behavioral development in mammals. This study explored the effects of transient neonatal Kiss blockade on long-term social behaviors in Wistar rats. Newborn rats of both sexes were injected with either a Kiss antagonist or vehicle during the postnatal testosterone surge, termed "minipuberty". In adolescence and adulthood, social behaviors, hypothalamic Kiss receptor levels, and serum levels of Gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), testosterone, and follicle-stimulating hormone (FSH) were assessed. Results showed that neonatal Kiss modulates testosterone differently in males and females, influencing social communication and long-term social skills. Increased exploratory behavior was observed, with males exhibiting heightened sexual impulsiveness without anxiety changes. Altered hypothalamic-pituitary-gonadal hormone levels due to Kiss blockade may help explain some results. These findings highlight the critical role of neonatal Kiss in shaping lifelong social interactions and communication in a sex-dependent manner.