title: Time-course changes of hormones and cytokines by lipopolysaccharide and its relation with anorexia.
abstract: We assessed the time course effects of lipopolysaccaride (LPS) on food intake, cytokines, and hormones in rats and evaluated the relation between LPS-induced anorexia and its possible causative factors. Food intake was reduced 2 h after LPS injection (500 microg/kg, intraperitoneally) and remained decreased for 24 h. Plasma TNF-alpha and IL-6 levels increased by LPS administration at 0.5 and 2 h, and at 2 and 4 h, respectively. Plasma leptin and glucose levels were elevated at 8 and 16 h, and insulin levels were elevated at 2, 4, 8, and 16 h in the LPS-injected group, as compared to the counterpart controls. IL-6 levels in the CSF were elevated at 2 and 4 h. Hypothalamic cytokines tended to increase as early as 0.5 h after LPS injection and remained increased until 16 h. LPS-induced anorexia was attenuated in insulin-deficient STZ rats and was abolished by insulin treatment. The hypothalamic expression of NPY, a target of insulin's anorexic effect, was decreased 2 h after LPS administration, and central NPY injection (3 nM) prevented LPS-induced anorexia. In conclusion, cytokines, insulin, and leptin levels evidence different time courses by LPS administration. In LPS-induced anorexia, insulin may constitute a newly found causative factor, whereas leptin appears to be uninvolved in an early period in rats.
authors.affiliation: Department of Physiology, College of Medicine, Yeungnam University, Daegu, Korea.
authors.forename: Yong-Woon
authors.initials: YW
authors.lastname: Kim
authors.forename: Keon-Ho
authors.initials: KH
authors.lastname: Kim
authors.forename: Dong-Kuk
authors.initials: DK
authors.lastname: Ahn
authors.forename: Hee-Sun
authors.initials: HS
authors.lastname: Kim
authors.forename: Jong-Yeon
authors.initials: JY
authors.lastname: Kim
authors.forename: Dong Chul
authors.initials: DC
authors.lastname: Lee
authors.forename: So-Young
authors.initials: SY
authors.lastname: Park
mesh_terms: D000818:Animals; D000855:Anorexia / Q000139:chemically induced / Q000378:metabolism*; D016207:Cytokines / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004435:Eating / Q000187:drug effects; D007004:Hypoglycemic Agents / Q000378:metabolism / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D007328:Insulin / Q000378:metabolism* / Q000494:pharmacology; D015850:Interleukin-6 / Q000097:blood / Q000134:cerebrospinal fluid; D020738:Leptin / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008297:Male; D009478:Neuropeptide Y / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D016207:Cytokines; D007004:Hypoglycemic Agents; D007328:Insulin; D015850:Interleukin-6; D020738:Leptin; D008070:Lipopolysaccharides; D009478:Neuropeptide Y; D014409:Tumor Necrosis Factor-alpha