title: Inhibitory effect of corticotropin-releasing factor on food intake in the bullfrog, Aquarana catesbeiana.
abstract: Corticotropin-releasing factor (CRF) and CRF-related peptides exert hypophysiotropic and anorexigenic effects in mammals and teleost fish. In anuran amphibians, CRF acts as a potent stimulator of thyrotropin release from the pituitary. According to our recent study, CRF also acts as an anorexigenic factor for the cessation of food intake in the metamorphosing bullfrog larvae. However, the anorexigenic action of CRF has not been confirmed in adult bullfrogs. In this context, we examined the effect of feeding status on the expression level of the CRF transcript in the hypothalamus of the adult bullfrog. Levels of CRF mRNA in the hypothalami from bullfrogs fasted for 7 days were lower than in those from the bullfrogs that had been fed normally. Subsequently, we developed a method for measuring food intake in adult bullfrogs, and then investigated the effect of CRF on their food consumption in these animals. Intracerebroventricular (ICV) administration of CRF at 1 and 10pmol/g body weight (BW) induced a significant decrease of food intake during 60min. The CRF-induced anorexigenic action was blocked by treatment with a CRF receptor 1/CRF receptor 2 antagonist, α-helical CRF((9-41)), at 100pmol/g BW. These results provide direct evidence for the inhibitory effect of CRF on food intake, and suggest the involvement of CRF in the regulation of feeding through a CRF receptor-signaling pathway in the adult bullfrog.
authors.affiliation: Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Morimoto
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Reiko
authors.initials: R
authors.lastname: Okada
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mochida
authors.forename: Minoru
authors.initials: M
authors.lastname: Uchiyama
authors.forename: Sakae
authors.initials: S
authors.lastname: Kikuyama
authors.forename: Kouhei
authors.initials: K
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D001067:Appetite Depressants / Q000494:pharmacology; D001835:Body Weight; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects*; D005215:Fasting / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D057967:Infusions, Intraventricular; D010446:Peptide Fragments / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D011892:Rana catesbeiana / Q000502:physiology*; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors; D015398:Signal Transduction; D013997:Time Factors; D000099052:CRF Receptor, Type 1
chemical_list: D001067:Appetite Depressants; C101531:CRF receptor type 2; D010446:Peptide Fragments; D012333:RNA, Messenger; D018019:Receptors, Corticotropin-Releasing Hormone; D000099052:CRF Receptor, Type 1; D003346:Corticotropin-Releasing Hormone; C045089:corticotropin releasing hormone (9-41)