The role of cytokines in the lipopolysaccharide-induced sick euthyroid syndrome in mice.
To evaluate the role of cytokines in the sick euthyroid syndrome, we tried to establish an animal model of non-thyroidal illness in mice by the administration of a sub-lethal dose of bacterial endotoxin (lipopolysaccharide; LPS) which induces a variety of cytokines, including tumour necrosis factor (TNF alpha), interleukin-1 (IL-1 alpha), interleukin-6 (IL-6) and interferon-gamma (IFN gamma). When compared with pair-fed controls, a single dose of LPS resulted in (a) systemic illness, (b) induction of TNF alpha and IL-6 and (c) a decrease of liver 5'-deiodinase mRNA from 4 h onwards followed by a decrease of serum tri-iodothyronine (T3) and thyroxine (T4) at 8 h and of serum free T3 (fT3) and free T4 (fT4) at 24 h; serum TSH remained unchanged. We then studied whether a single dose or a combination of IL-1 alpha, TNF alpha, IL-6 or IFN gamma could induce the sick euthyroid syndrome in mice, again using pair-fed controls. None of the cytokines except IL-1 alpha caused systemic illness, and IL-1 alpha was the only cytokine that decreased liver 5'-deiodinase mRNA transiently. IL-1 alpha, TNF alpha or IL-6 did not decrease serum T3, T4 and TSH, but administration of IFN gamma decreased serum T4, T3 and fT3 in a dose-dependent manner without changes in serum TSH. Administration of all four cytokines together had no synergistic effects; observed changes were of a smaller magnitude than after LPS. The following conclusions were reached.(ABSTRACT TRUNCATED AT 250 WORDS)
Boelen
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A
Department of Endocrinology, Academic Medical Centre, University of Amsterdam, The Netherlands.
Platvoet-ter Schiphorst
M C
MC
Bakker
O
O
Wiersinga
W M
WM
D000818:Animals; D016207:Cytokines / Q000494:pharmacology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005067:Euthyroid Sick Syndromes / Q000097:blood / Q000201:enzymology / Q000276:immunology*; D005260:Female; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology; D007453:Iodide Peroxidase / Q000378:metabolism; D008070:Lipopolysaccharides; D008099:Liver / Q000201:enzymology; D051379:Mice; D008815:Mice, Inbred Strains; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D014284:Triiodothyronine; D007371:Interferon-gamma; D013972:Thyrotropin; D007453:Iodide Peroxidase; D013974:Thyroxine