Interleukin-6 levels in the central nervous system are negatively correlated with fat mass in overweight/obese subjects

J Clin Endocrinol Metab. 2003 Sep;88(9):4379-83. doi: 10.1210/jc.2002-021733.


Recently, we demonstrated that intracerebroventricular injection of IL-6 increases energy expenditure and decreases body fat in rodents. Therefore, IL-6 may play a role in appetite and body weight control in the central nervous system. In the present study we evaluated cerebrospinal fluid (CSF) and serum IL-6 levels in humans in relation to body fat content and to CSF and serum levels of leptin. Thirty-two healthy overweight/obese male subjects with a body mass index range of 29.3-36.0 kg/m(2) were studied. Total and sc body fat were measured by dual energy x-ray absorptiometry and computed tomography, respectively. CSF IL-6 levels were in some individuals higher than serum IL-6 levels and correlated negatively with total body weight, sc and total body fat. In contrast, CSF leptin levels were 30-60 times lower than serum leptin levels and correlated positively with serum leptin, body weight, sc and total body fat. Furthermore, there was a negative correlation between CSF IL-6 and leptin. In conclusion, CSF IL-6 differs in many ways from CSF leptin. CSF IL-6 may be locally produced rather than serum derived, and body fat-regulating regions in the central nervous system may be exposed to insufficient IL-6 levels in more severe obesity.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorptiometry, Photon
  • Adipose Tissue / anatomy & histology*
  • Adult
  • Body Composition / physiology*
  • Body Weight / physiology
  • Central Nervous System / metabolism*
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Interleukin-6 / cerebrospinal fluid*
  • Leptin / blood
  • Leptin / cerebrospinal fluid
  • Male
  • Middle Aged
  • Obesity / cerebrospinal fluid*
  • Obesity / pathology
  • Serum Albumin / metabolism


  • Interleukin-6
  • Leptin
  • Serum Albumin