The central anorexigenic mechanism of adrenocorticotropic hormone involves the caudal hypothalamus in chicks |
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| Institution: | 1. Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA;2. Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, USA;1. Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil;2. Departamento de Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, MG, Brazil;3. Instituto Nacional de Ciência e Tecnologia em Nanobiofarmacêutica (INCT-Nanobiofar), Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil,;1. The Core Laboratory of the First Affiliated Hospital, Lanzhou University, 1 Donggang West Road, Lanzhou 730000, China;2. Key Laboratory for Gastrointestinal Diseases of Gansu Province, Lanzhou 730000, China;3. Institute of Biochemistry and Molecular Biology, School of Life Sciences, 222 Tianshui South Road, Lanzhou 730000, China;4. Key Laboratory of Preclinical Study for New Drugs of Gansu Province, 222 Tianshui South Road, Lanzhou 730000, China |
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| 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 1 h 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. |
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