Effect of 24 h Fasting on Gene Expression of AMPK, Appetite Regulation Peptides and Lipometabolism Related Factors in the Hypothalamus of Broiler Chicks

Abstract

ABSTRACT:The 5'-adenosine monophosphate-activated protein kinase (AMPK) is a key part of a kinase-signaling cascade that acts to maintain energy homeostasis. The objective of this experiment was to investigate the possible effects of fasting and refeeding on the gene expression of hypothalamic AMPK, some appetitive regulating peptides and lipid metabolism related enzymes. Seven-day-old male broiler (Arbor Acres) chicks were allocated into three equal treatments: fed ad libitum (control); fasted for 24 h; fasted for 24 h and then refed for 24 h. Compared with the control, the hypothalamic gene expression of AMPK2, AMPK1, AMPK2, AMPK1, Ste20-related adaptor protein  (STRADβ), mouse protein 25 (MO25α) and agouti-related peptide (AgRP) were increased after fasting for 24 h. No significant difference among treatments was observed in mRNA levels of AMPK1, AMPK2, LKB1 and neuropeptide Y (NPY). However, the expression of MO25, pro-opiomelanocortin (POMC), corticotropin-releasing hormone (CRH), ghrelin, fatty acid synthase (FAS), acetyl-CoA carboxylase  (ACC), carnitine palmitoyltransferase 1 (CPT-1) and sterol regulatory element binding protein-1 (SREBP-1) were significantly decreased. The present results indicated that 24 h fasting altered gene expression of AMPK subunits, appetite regulation peptides and lipometabolism related factors in chick's hypothalamus; the hypothalamic FAS signaling pathway might be involved in the AMPK regulated energy homeostasis and/or appetite regulation in poultry.

Hypothalamic AMPK as a Regulator of Energy Homeostasis

“…Besides that, activated AMPK also induces CPT-1a in the mitochondria [ 77 ] and the induction of both CTP-1 isoforms results in increasing mRNA expression of AgRP and NPY genes by the activation of brain-specific homeobox transcription factor (BSX) together with the forkhead box protein O1 (FoxO1) and the phosphorylated cyclic adenosine monophosphate response-element binding protein (pCREB) [ 141 ]. Additionally, AMPK suppresses the synthesis of ACC, fatty acid synthase (FAS), and other enzymes for lipid biogenesis in many tissues, including the hypothalamus, by inhibiting expression of the transcription factor sterol-regulatory-element-binding transcription factor 1 (SREBP1c) [ 142 , 143 ].…”

Effect of dexamethasone on hypothalamic expression of appetite-related genes in chickens under different diet and feeding conditions

“…The release of these neuropeptides is closely associated with the feeding state and dietary energy level. For example, the fasting for 24 h decreased the hypothalamic POMC and CRH genes expression, but increased the AgRP gene expression in chicks [ 4 ]. The mice fed with high fat diet had the lower NPY and AgRP mRNA levels [ 5 , 6 ].…”

The role of cinnamon as a modulator of the expression of genes related to antioxidant activity and lipid metabolism of laying quails

“…The primers used for Acetyl-CoA Carboxylase ( ACC ) and fatty acid synthase ( FAS ) were designed according to Lei and Lixian [ 18 ]; primers used for apolipoprotein A-I ( APOAI) and apolipoprotein B ( APOB ) were designed according to Jiang et al [ 19 ], and primers used for the superoxide dismutase ( SOD ), glutathione peroxidase 7 ( GPx7 ), and estrogen receptor 2 ( ESR2) reactions were designed based on the gene sequences deposited at www.ncbi.nlm.nih.gov (accession numbers, NM_205064.1, NM_001163245.1 e XM_015865463.1, respectively) using the site www.idtdna.com . Two endogenous controls, ß-actin and GAPDH , were tested, and ß-actin (accession number L08165) was selected because its amplification efficiency was higher and similar to the amplification efficiency of the target genes ( Table 2 ).…”