Key Peptides Linked to Delayed Puberty in Ewes Identified

Puberty is a complex biological process involving a cascade of hormonal changes, with the hypothalamic-pituitary-gonadal (HPG) axis playing a central role. The timely onset of puberty is crucial for reproductive success in many species, including livestock. Disruptions can lead to significant economic and welfare challenges. A key regulatory system involves KNDy neurons (Kisspeptin, Neurokinin B, Dynorphin A) in the brain, which are known to modulate the release of GnRH (Gonadotropin-releasing hormone), the master hormone of reproduction. This study specifically addresses how the interplay of kisspeptin-10, neurokinin B, and dynorphin A differs between normal and delayed puberty in ewes.

The study revealed significant alterations in the levels of all three peptides in ewes with delayed puberty compared to their normally developing counterparts. In the delayed group, kisspeptin-10 concentrations were markedly reduced by 35% (p<0.01) during the peri-pubertal stage, indicating a potential deficiency in this crucial pubertal activator. Similarly, neurokinin B levels, another stimulatory peptide, were 28% lower (p<0.02) in ewes with delayed puberty. Conversely, dynorphin A, an inhibitory neuropeptide, showed a substantial 2.1-fold increase (p<0.005) in the delayed puberty group, suggesting an overactive inhibitory brake on the pubertal process. These findings highlight a coordinated dysregulation of the KNDy system. > The most striking finding was the 2.1-fold increase in dynorphin A in delayed puberty, suggesting its potent inhibitory role in preventing timely reproductive maturation.