Acute and chronic administration of immunomodulators induces anorexia in Zucker rats

F. Lugarini, B. J. Hrupka, G. J. Schwartz, C. R. Plata-Salaman, W. Langhans

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


To investigate the possible involvement of leptin signaling in lipopolysaccharide (LPS) anorexia, we compared the anorectic effect of LPS in genetically obese (fa/fa) Zucker rats and in their lean (Fa/?) counterparts. The effects of interleukin-1β (IL-1β) and muramyl dipeptide (MDP) were also tested. LPS [100 μg/kg body weight (BW)], IL-1β (2 μg/kg BW) and MDP (2.2 mg/kg BW) injected intraperitoneally (i.p.) at lights out reduced food intake similarly in obese and lean rats. LPS injection at 500 or 1000 μg/kg BW (i.p.) also reduced food intake and BW similarly in obese and lean rats, but obese regained BW faster than lean rats. LPS (2.45 μg or 9.8 μg/h/rat) administered chronically with i.p. implanted osmotic pumps reduced food intake similarly on experimental day 1, regardless of the genotype. After day 3, the lean rats' anorectic response and recovery were dose-dependent, whereas the anorectic response in obese rats was minimally affected by dose (significant dose effect only on day 3). Again, obese rats regained lost BW faster than lean rats. These results do not support a role for leptin as the sole mediator of anorexia induced by bacterial products (LPS and MDP) and IL-1β.

Original languageEnglish (US)
Pages (from-to)165-173
Number of pages9
JournalPhysiology and Behavior
Issue number1
StatePublished - Jan 31 2005
Externally publishedYes


  • Anorexia
  • Body weight
  • Cytokines
  • Feeding
  • Food intake
  • Genotype
  • Interleukin
  • Leptin
  • Obesity

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Behavioral Neuroscience


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