title: The central anorexigenic mechanism of adrenocorticotropic hormone involves the caudal hypothalamus in chicks.
abstract: Adrenocorticotropic hormone (ACTH), consisting of 39 amino acids, is most well-known for its involvement in an organism's response to stress. It also participates in satiety, as exogenous ACTH causes decreased food intake in rats. However, its anorexigenic mechanism is not well understood in any species and its effect on appetite is not reported in the avian class. Thus, the present study was designed to evaluate central ACTH's effect on food intake and to elucidate the mechanism mediating this response using broiler chicks. Chicks that received intracerebroventricular (ICV) injection of 1, 2, or 4 nmol of ACTH reduced food intake, under both ad libitum and 180 min fasted conditions. Water intake was also reduced in ACTH-injected chicks under both feeding conditions, but when measured without access to feed it was not affected. Blood glucose was not affected in either feeding condition. Following ACTH injection, c-Fos immunoreactivity was quantified in key appetite-associated hypothalamic nuclei including the ventromedial hypothalamus (VMH), dorsomedial hypothalamus, lateral hypothalamus (LH), arcuate nucleus (ARC) and the parvo- and magno-cellular portions of the paraventricular nucleus. ACTH-injected chicks had increased c-Fos immunoreactivity in the VMH, LH, and ARC. Hypothalamus was collected at 1h post-injection, and real-time PCR performed to measure mRNA abundance of some appetite-associated factors. Neuropeptide Y, pro-opiomelanocortin, glutamate decarboxylase 1, melanocortin receptors 2-5, and urocortin 3 mRNA abundance was not affected by ACTH treatment. However, expression of corticotropin releasing factor (CRF), urotensin 2 (UT), agouti-related peptide (AgRP), and orexin (ORX), and melanocortin receptor 1 (MC1R) mRNA decreased in the hypothalamus of ACTH-injected chicks. In conclusion, ICV ACTH causes decreased food intake in chicks, and is associated with VMH, LH, and ARC activation, and a decrease in hypothalamic mRNA abundance of CRF, UT, AgRP, ORX and MC1R.
authors: Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
authors: Steven L
authors: SL
authors: Shipp
authors: Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
authors: Jiaqing
authors: J
authors: Yi
authors: Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, USA.
authors: Sami
authors: S
authors: Dridi
authors: Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
authors: Elizabeth R
authors: ER
authors: Gilbert
authors: Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA. Electronic address: macline2@vt.edu.
authors: Mark A
authors: MA
authors: Cline
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D001067:Appetite Depressants / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects; D001786:Blood Glucose / Q000378:metabolism; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D007276:Injections, Intraventricular; D009479:Neuropeptides / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism
chemical_list: D001067:Appetite Depressants; D001786:Blood Glucose; D009479:Neuropeptides; D016760:Proto-Oncogene Proteins c-fos; D000324:Adrenocorticotropic Hormone
keywords: Adrenocorticotropic hormone; Chick; Food intake; Hypothalamus