title: Effects of recombinant human leptin administration on hepatic lipid metabolism in yellow catfish Pelteobagrus fulvidraco: in vivo and in vitro studies.
abstract: The present study was conducted to investigate the effects and mechanism of leptin influencing lipid metabolism in yellow catfish Pelteobagrus fulvidraco. To this end, hepatic lipid (in vivo experiment) and intracellular triglyceride (TG) (in vitro experiment) content, the activities and/or expression level of several enzymes (CPT-1, 6PGD, G6PD, FAS, ME and ICDH) as well as the mRNA expression of transcription factors (PPARα, PPARγ and SREBP-1) involved in lipid metabolism were determined. Using the primary hepatocytes of yellow catfish, specific inhibitors AG490 (JAK-STAT inhibitor) and wortmannin (IRS-PI3K inhibitor) were used to explore the signaling pathways of leptin effects on lipid metabolism. Intraperitoneal injection of recombinant human leptin (rt-hLEP) significantly reduced hepatic lipid content, activities of lipogenic enzymes (6PGD, G6PD, ME, ICDH and FAS) as well as mRNA levels of 6PGD, G6PD, FAS, PPARγ and SREBP-1 genes, but up-regulated activity and mRNA level of CPT-1 and PPARα. Using primary hepatocytes, rt-hLEP incubation also reduced intracellular TG content, mRNA levels of G6PD and PPARγ genes, but enhanced mRNA levels of PPARα, CPT-1 and SREBP-1. Leptin-induced effects could partially be reversed by specific inhibitors AG490, suggesting that JAK-STAT signaling pathways played important roles in the process of leptin-induced changes in lipid metabolism. Wortmannin significantly suppressed the decrease of TG content induced by leptin, reflecting that IRS-PI3K was involved in the leptin-mediate changes as well. To our knowledge, the present study provides, for the first time, evidence that rt-hLEP can increase lipolysis and reduce lipogenesis at the both enzymatic and molecular levels in fish with the combination of in vivo with in vitro studies, which serves to increase our understanding into the roles and mechanisms of leptin regulating lipid metabolism in fish.
authors: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China.
authors: Yu-Feng
authors: YF
authors: Song
authors: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China.
authors: Kun
authors: K
authors: Wu
authors: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China. Electronic address: txy7933@163.com.
authors: Xiao-Ying
authors: XY
authors: Tan
authors: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China.
authors: Li-Han
authors: LH
authors: Zhang
authors: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China.
authors: Mei-Qin
authors: MQ
authors: Zhuo
authors: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China.
authors: Ya-Xiong
authors: YX
authors: Pan
authors: Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Center of Hubei Province, Wuhan 430070, China.
authors: Qi-Liang
authors: QL
authors: Chen
mesh_terms: D000818:Animals; D002397:Catfishes / Q000254:growth & development / Q000378:metabolism*; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D066298:In Vitro Techniques; D020738:Leptin / Q000008:administration & dosage* / Q000494:pharmacology; D050356:Lipid Metabolism / Q000187:drug effects*; D050155:Lipogenesis / Q000187:drug effects; D008066:Lipolysis / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000008:administration & dosage* / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D014280:Triglycerides / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D020738:Leptin; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014280:Triglycerides
keywords: Leptin; Lipid deposition; Lipid metabolism; Pelteobagrus fulvidraco; Signaling pathway