title: Glucocorticoids inhibited hypothalamic target of rapamycin in high fat diet-fed chicks.
abstract: The present study was conducted with broiler chicks exposed to dexamethasone (DEX) to explore its effects on hypothalamic target of rapamycin (TOR) signaling and regulating appetite in diets containing different energy levels. At 5 d age, 48 chicks were divided into one of 4 groups: high-fat diet (HFD) or low-fat diet (LFD) and intracerebroventricular (ICV) injected with either dexamethasone (DEX; 4 μg/2 μL) or saline at 10 d age. The results showed that DEX significantly inhibited gene expression of cocaine- and amphetamine-regulated transcripts (CART), melanocortin receptor 4 (MC4R), and corticotropin-releasing hormone (CRH), and inhibited the protein level of the phospho-TOR compared with the control in HFD-fed chicks (P<0.05) but not in LFD-fed chicks (P>0.05). After DEX treatment, hypothalamic agouti-related peptide levels were decreased significantly in HFD-fed chicks (P<0.05) but not in LFD-fed chicks (P>0.05). Compared to the control, DEX-treated chicks did not present any significant changes in neuropeptide Y gene expression with either HFD or LFD (P>0.05), but pro-opiomelanocortin levels were depressed by ICV DEX treatment with both diets (P<0.05). In conclusion, glucocorticoids (GC) downregulated hypothalamic gene expression of CART, CRH, and MC4R in HFD-fed chicks, suggesting that the regulatory network formed by these genes is associated with the appetite control during stress. The TOR pathway may be involved in the regulation of GC on appetite-related genes.
authors.affiliation: Department of Animal Science, Shandong Agricultural University, Shandong Key Lab for Animal Biotechnology and Disease Control, Taian, Shandong 271018, China.
authors.forename: L
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Animal Science, Shandong Agricultural University, Shandong Key Lab for Animal Biotechnology and Disease Control, Taian, Shandong 271018, China.
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Animal Science, Shandong Agricultural University, Shandong Key Lab for Animal Biotechnology and Disease Control, Taian, Shandong 271018, China.
authors.forename: H
authors.initials: H
authors.lastname: Jiao
authors.affiliation: Department of Animal Science, Shandong Agricultural University, Shandong Key Lab for Animal Biotechnology and Disease Control, Taian, Shandong 271018, China.
authors.forename: J
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Animal Science, Shandong Agricultural University, Shandong Key Lab for Animal Biotechnology and Disease Control, Taian, Shandong 271018, China hailin@sdau.edu.cn.
authors.forename: H
authors.initials: H
authors.lastname: Lin
mesh_terms: D000818:Animals; D030161:Avian Proteins / Q000235:genetics* / Q000378:metabolism; D002645:Chickens / Q000235:genetics / Q000502:physiology*; D003907:Dexamethasone / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D005938:Glucocorticoids / Q000494:pharmacology*; D007031:Hypothalamus / Q000378:metabolism; D057967:Infusions, Intraventricular; D008297:Male; D010766:Phosphorylation; D011897:Random Allocation; D058570:TOR Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism
chemical_list: D030161:Avian Proteins; D005938:Glucocorticoids; D003907:Dexamethasone; D058570:TOR Serine-Threonine Kinases
keywords: TOR; appetive peptides; glucocorticoids; high/low fat diet