Relationship between Blood Progesterone Concentration and Hypothalamic Gonadotropin-Inhibitory Hormone Expression in Female Japanese Quails

Infertility or low fertility in animals impose financial burdens on farmers. The recognition of the factors affecting fertility is a matter of critical importance for the improvement of reproductive activity .Ovarian hormones affects reproductive status, secondary sexual characteristics, metabolic status, and behavior. The relationship between progesterone and reproduction is an important topic for poultry farmers. The investigation of progesterone hormone concentration and hypothalamic pituitary gonadotropin (HPG) axis can solve some of the problems associated with fertility problems. The examination of these issues can facilitate the identification of the negative feedback effects of reduced progesterone after ovulation, role of HPG axis, and relationship between this hormone and expression of gonadotropin-inhibitory hormone (GnIH) neurons. Gonadotropin-releasing hormone (GnRH) and GnIH neurons are located in the hypothalamus. The GnRH neuron has a GnIH G-protein coupled receptor 145, through which GnIH acts on GnRH neurons. Regarding this, the present study was conducted to investigate the relationship between progesterone concentration and HPG during ovulation. This study was conducted on 10 Japanese quails in two groups. The groups were anesthetized with formalin 2 h before and 2 h after ovulation. After collecting blood samples, fixation was performed for brain sampling. The hypothalamic tissue sections were stained by immunohistochemistry, and the GnIH neurons in the paraventricular nucleus were counted. Furthermore, the plasma progesterone concentrations were measured for each of the birds. The results demonstrated an indirect correlation between plasma progesterone concentrations and negative feedback effect of progesterone on HPG axis after ovulation. The number of the GnIH neurons in the Japanese quails was affected by the endocrine system (progesterone). The findings of the present study revealed the effect of progesterone on the HPG axis in Japanese quails

Keywords:

HPGaxis , GnIH , Progesterone , Japanesequail