NEUROPEPTIDE REGULATION OF FEEDING AND GROWTH-HORMONE SECRETION IN FISH

In goldfish bombesin (BBS)/gastrin-releasing peptide (GRP)-like and cholecystokinin (CCK)/gastrin-like immunoreactive (IR) peptides are present in the pituitary, and ventro-posterior hypothalamus and hypothalamic inferior lobes of the brain feeding centre. Receptor autoradiography studies in goldfish indicate BBS/GRP and CCK/gastrin specific binding sites in similar pituitary and brain areas. BBS and sulfated CCK8 inhibit food intake in goldfish when administered either intraperitoneally (ip) or into the brain third ventricle (icy), and act concomitantly to elevate serum growth hormone (GH). BBS and CCK also stimulate GH release from perifused goldfish pituitary fragments. Overall. BBS and CCK have potent satiety effects in goldfish, and may provide links to the neuroendocrine system for postprandial GH regulation. Other neuroendocrine factors involved in the regulation of GH secretion, including neuropeptide Y, gonadotropin-releasing hormone and GH-releasing hormone may also play a role in altering food intake in fish.