title: Relationship between brain gonadotrophin-releasing hormone (GnRH) and seasonal reproductive cycle of "caribe colorado," Pygocentrus notatus.
abstract: Immunoreactive gonadotrophic hormone-releasing hormone (ir-GnRH) was detected in hypothalamic and telencephalic extracts of the Venezuelan freshwater fish "caribe colorado," Pygocentrus notatus. Hypothalamic ir-GnRH from female fish demonstrated displacement curves parallel to those of synthetic mammalian luteinizing hormone-releasing hormone (LHRH). The content of hypothalamic and telencephalic ir-GnRH from female fish was more than four-fold greater than that of male animals. Also, fluctuations that depended on the reproductive state and environmental conditions (rainfall) occurred in females but not in males. Thus, ir-GnRH levels were higher in hypothalamic and telencephalic extracts from sexually mature females than in those from fish sampled outside the climatically determined breeding season.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D005260:Female; D005399:Fishes / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D010906:Pituitary Hormone-Releasing Hormones / Q000378:metabolism*; D012098:Reproduction; D012621:Seasons; D012727:Sex Characteristics; D013687:Telencephalon / Q000378:metabolism
chemical_list: D010906:Pituitary Hormone-Releasing Hormones