Kisspeptin is a neuropeptide that modulates the endocrine system. It plays a role in regulating the maturation of the hypothalamic-pituitary axis and vertebrate reproduction.
The kisspeptin receptors Kiss1 and Kiss2 are upstream regulators of the GnRH pulse generation. These receptors are located on a peptide called pep 234 and pep 359. Pep 234 antagonizes Kiss1r signaling while pep 359 inhibits Kiss2 activation of both receptors.
In this study, we sought to determine the effects of kisspeptin-10 on plasma testosterone and LH concentrations in adult male hamsters. We randomly assigned 38 adult male hamsters to one of two treatment groups.
Before and after the injection of kisspeptin-10, the serum level of plasma testosterone and LH was measured. The mean% and peak LH and testosterone responses were also determined.
Plasma testosterone levels increased significantly after kisspeptin-10 administration. Plasma testosterone level was notably higher in the saline+kisspeptin group. However, there was no significant difference in post-kisspeptin plasma LH levels.
After the inflammatory response, the testis was insensitive to the steroid, resulting in reduced kisspeptin-immunoreactive cells. This may be due to downregulation of kisspeptin.
Kisspeptin is present in the hypothalamus, which regulates gonadotropin secretion. A decrease in kisspeptin results in infertility. Although the exact mechanism is not known, it appears that a lack of kisspeptin activity reduces the number of spermatogonia.
Kisspeptin is released by the hypothalamus during puberty. When exposed to testosterone, it increases the transcriptional expression of the androgen receptor in the rat testis.