The influence of various kisspeptins on the reproductive function of Bos taurus (review)

Kisspeptins (KP) are a family of peptides of various lengths with a receptor (KISS1R). Kisspeptins with gonadotropin hormone-releasing hormone (GnRH), gonadotropins (luteinizing hormone and follicle-stimulating hormone) and sexual steroids are important regulators of reproductions of various animals (S. Ohkura et al., 2009; K.-L. Hu et al., 2018). Active study of KP began in 2003. However, at present, there is not enough information about the possibilities with the help of KP to purposefully and effectively control the sexual cycle of Bos taurus cows (especially the milk direction) (B.R. Alves et al., 2015; T. Songraphasuk et al., 2021). The KP is produced mainly in neurons of various nuclei of the hypothalamus (V. Prashar et al., 2023). Considering that the location of neurons producing the KP is specific, the approaches to control with their help the reproductive function may vary (A. Gunn et al., 2020). Kisspeptin is synthesized using the gene kiss1 . Initially, the KP is hydrolyzed to the KP-53, which later breaks up to shorter peptides (KP-14, KP-13 and KP-10) with various biological activity (A.E. Oakley et al., 2009; J. Tomikawa et al., 2010). Neurons producing KP are also coexption of peptide neurokinin B (NKB) and dinorfin, which determined the name of this population of nerve cells (KNDy-neurons, kisspeptin/neurokinin B/dinorphin) (R.L. Goodman et al., 2013; Q. Xie et al., 2022). In cattle KNDY-neurons are mainly fixed in the arcuate nucleus of the hypothalamus, which is considered important for both positive and negative reverse regulation by sex steroids of the synthesis of GnRH (A. Hassaneen et al., 2016; Y. Uenoyama et al., 2021). Using the histochemical method, it was demonstrated that the activation of KNDy-neurons in cattle depends on the phase of the sexual cycle (A. Hassaneen et al., 2016). Kisspeptin-, neurokinin В-, and dinorfin-immunoreactive cellular bodies and fibers detecting throughout the arcuathed nucleus of the hypothalamus in all phases. Unlike the arcuathed nucleus, numerous kisspeptin-immunoreactive cellular bodies were found in the reservoir region of the hypothalamus in the follicular phase, while only a few immunoreactive cellular bodies are recorded in the luteal phase. As for neurokinin, in the reservoir region a small amount of neurokinin of B-immunoreactive cellular bodies and fibers in both the follicular and lutein phase is naked. Dinorfin-immunoreactive cellular bodies and fibers in the follicular phase were larger than in luteal phase. In this regard, cattle are closer to sheep and primates, including human (V.M. Tanco et al., 2016). Since the initial identification of KNDy-neurons producing KP, there are a large number of unresolved issues relating to the function of various populations of these nerve cells, depending on the location, as well as the possibilities of new technologies for their study, including in relation to Bos taurus . There is a need to study various concentrations of kisspeptins and their influence on the ovulation of cows. This review discusses the basic information about the location and structural-functional characteristics of the Bos taurus KP, the distribution and functions of the KP neurons in the brain, the content of the KP in the blood and their effect on the organs of the reproductive system. Separately data on the exogenous regulation of KP functioning of the reproductive system Bos taurus are discussed. The emphasis is on scientific research data, the main object of which was Bos taurus animals.