Kisspeptins and the reproductive axis: potential applications to manage reproduction in farm animals.

The research article discusses the potential use of neuropeptide family, kisspeptins (Kp), in managing reproduction in farm animals. The study explores the role of kisspeptins in regulating the gonadotropin axis and stimulating gonadotropin secretion, with experimental models indicating that their administration can induce and synchronize ovulation.

Kisspeptins and their Role in the Gonadotropin Axis

• Kisspeptins, a family of neuropeptides, are primarily produced by two hypothalamic neuronal cell populations. These neuropeptides have recently gained attention as major regulators of the gonadotropin axis, a hormonal system responsible for the regulation of reproductive processes.
• The action of these peptides precedes that of the gonadotropin-releasing hormone (GnRH) cell population, suggesting their higher-level impact on the gonadotropin axis and hence on the reproductive processes.
• Extensive research over the past decade has indicated that kisspeptins have a role in almost all aspects of reproductive axis maturation and function.

Kisspeptins as Tools for Reproductive Manipulation

• Administering kisspeptins in mammals has shown to significantly stimulate gonadotropin secretion, primarily through the stimulation of GnRH release.
• The researchers conducted experiments on ewes and pony mares to test the effectiveness of kisspeptin administration in inducing and synchronizing ovulations.
• In ewes, an infusion of kisspeptins led to a surge in luteinizing hormone (LH), a hormone involved in ovulation and development of corpus luteum. This surge was observed in all kisspeptin-treated animals within 2 hours of the infusion.
• In pony mares, however, a continuous kisspeptin infusion over three days during the late follicular phase did not result in synchronized ovulation.

Kisspeptins’ Potential in Activating Reproductive Function

• On the other hand, kisspeptins were found effective in kick-starting the reproductive function in acyclic or non-cycling animals. When prepubertal ewe lambs were administered kisspeptins in a pulsatile manner, it activated ovarian function, leading to enhanced ovarian steroidogenesis, stimulation of LH preovulatory surge, and subsequent ovulation.
• In non-breeding, anestrous ewes, a low dose of kisspeptin infusion led to the immediate and sustained release of gonadotropins, leading later to an LH surge. This mimicked normal hormonal changes observed during the estrous cycle follicular phase and was associated with a high proportion of ewes ovulating.

Future Work and Implications

• Despite the promising findings, the authors indicate that further work is required to determine the optimal dosage and duration of treatment for each species.
• They also emphasize the need for the development of influential analogs or long-term release formulations for large-scale applications in domestic animals.