Synergistic Roles of interleukin-6, interleukin-1, and Tumor Necrosis Factor in the Adrenocorticotropin Response to Bacterial Lipopolysaccharide in Vivo

Endocrinology. 1993 Mar;132(3):946-52. doi: 10.1210/endo.132.3.8382602.

Abstract

Administration of lipopolysaccharide (LPS) results in activation of the hypothalamic-pituitary-adrenal axis. LPS induces the release of a number of proinflammatory cytokines, i.e. interleukin-1 (IL-1), IL-6, and tumor necrosis factor (TNF), which activate the hypothalamic-pituitary-adrenal axis as well and may mediate the effects of LPS. Variations in the kinetics of appearance of IL-1, TNF, and IL-6 after LPS challenge suggested that these cytokines may play different roles at different times. To elucidate the mutual dependence and contribution of individual cytokines in the course of LPS-induced ACTH release, we used blocking antibodies to IL-6, TNF, and the IL-1 receptor. Our results demonstrate that anti-IL-6 antibody abrogated ACTH induction throughout the course of the response both 2 and 4 h after LPS challenge. In contrast, anti-IL-1 receptor and anti-TNF antibody, given individually, blocked ACTH production at 4 h, but not at 2 h. Only combined administration of these two antibodies diminished, but did not eliminate, ACTH release at 2 h. This is the first demonstration that all three inflammatory cytokines are obligatory for LPS-induced elevation of plasma ACTH. In addition, these results suggest that IL-1, IL-6, and TNF play different roles in LPS-induced ACTH release.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adrenocorticotropic Hormone / blood
  • Adrenocorticotropic Hormone / metabolism*
  • Animals
  • Drug Interactions
  • Escherichia coli
  • Female
  • Humans
  • Hypothalamo-Hypophyseal System / drug effects
  • Hypothalamo-Hypophyseal System / physiology
  • Interleukin-1 / pharmacology*
  • Interleukin-6 / pharmacology*
  • Kinetics
  • Lipopolysaccharides / isolation & purification
  • Lipopolysaccharides / pharmacology*
  • Mice
  • Mice, Inbred C3H
  • Recombinant Proteins / pharmacology
  • Reference Values
  • Time Factors
  • Tumor Necrosis Factor-alpha / pharmacology*

Substances

  • Interleukin-1
  • Interleukin-6
  • Lipopolysaccharides
  • Recombinant Proteins
  • Tumor Necrosis Factor-alpha
  • Adrenocorticotropic Hormone