P-95: Seasonal Changes in Hypothalamic Gonadotropin-Inhibitory Hormone Expression in Alectoris Chukar
Gonadotropin-inhibitory hormone (GnIH), initially discovered in birds as a hypothalamic neuropeptide, inhibits the synthesis and release of gonadotropins via affecting GnRH neurons and gonadotropes. Therefore, it could be a key neuropeptide in regulating seasonal breeding in birds. The aim of the present study was to investigate the expression of GnIH in the hypothalamus of male and female chukar partridges during the breeding and non-breeding seasons.
Materials and methods
In breeding (May) and nonbreeding (January) seasons, the brains of male (n=10) and female (n=10) sexually mature chukar partridges were removed following fixation. Sections (30 μm) were prepared from the entire hypothalamus and stained immunohistochemically (GnIH antibody was provided by Prof. K. Tsutsui).
GnIH-immunoreactive (-IR) neurons were primarily found in PVN nucleus and few positive neurons detected in DMN nucleus. The number of GnIH-ir neurons were significantly lower in the breeding season than non-breeding season in both male and female partridges (P<0.05).
The results showed that GnIH neurons may play part in regulating the seasonal breeding in the chukar partridge.