Activity of body energy regulatory pathways in inflammation-induced anorexia.
Previous research has shown that reductions in body weight prior to induction of acute inflammation can attenuate inflammation-induced anorexia in male rats. In the current study, potential mechanisms responsible for this observation were examined. Specifically, the effect of a 12% prior reduction in body weight on serum leptin, insulin, and corticosterone; levels of interleukin-1 (IL-1), interleukin-6 (IL-6) in the serum, liver, and spleen; neuropeptide Y (NPY) and POMC mRNA levels in the arcuate nucleus (ARC) of the hypothalamus were examined 8 h after induction of acute inflammation. Rats with prior weight reduction had significantly lower serum leptin levels and gene expression of POMC in the ARC than normal-weight rats. In contrast, prior weight reduction altered neither NPY mRNA in the ARC, nor IL-1alpha, IL-1beta, and IL-6 levels in the serum, liver, and spleen. These results suggest that the attenuation of inflammation-induced anorexia by prior weight reduction is not due to altered cytokine activity, but rather to changes in energy regulatory systems that moderate the anorexic actions of IL-1beta and IL-6. One potential change may be reduced activity of the CNS melanocortin system induced by decreased circulating leptin.
Lennie
T A
TA
College of Nursing, Ohio State University, 1585 Neil Avenue, 43210-1289, Columbus OH, USA. lennie.2@osu.edu
Wortman
M D
MD
Seeley
R J
RJ
D000273:Adipose Tissue / Q000502:physiology; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D004734:Energy Metabolism / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D006728:Hormones / Q000097:blood; D017403:In Situ Hybridization; D007249:Inflammation / Q000378:metabolism* / Q000503:physiopathology*; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D009478:Neuropeptide Y / Q000096:biosynthesis; D011333:Pro-Opiomelanocortin / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013154:Spleen / Q000378:metabolism
D001786:Blood Glucose; D006728:Hormones; D007375:Interleukin-1; D015850:Interleukin-6; D009478:Neuropeptide Y; D012333:RNA, Messenger; D011333:Pro-Opiomelanocortin