Leptin causes body weight loss in the absence of in vivo activities typical of cytokines of the IL-6 family.
To investigate if leptin shares in vivo activities with interleukin (IL)-6 family cytokines, it was tested in normal mice for the ability, after a single injection, to induce the acute-phase protein serum amyloid A, to potentiate the induction by IL-1 of serum corticosterone and IL-6, and to inhibit the induction by lipopolysaccharide of serum tumor necrosis factor and, after seven daily injections, to cause body weight loss and to change peripheral blood cell counts. At a 0.5 mg/kg dose, leptin caused body weight loss but did not show any of the other activities above. At a dose of 5 mg/kg, which also caused body weight loss, leptin potentiated the induction by IL-1 of serum corticosterone and IL-6 but did not show any other activity. In addition to causing body weight loss, leptin shows only some of the in vivo activities typical of IL-6 family cytokines and only if used at a dose that exceeds the one sufficient to affect body weight. In vivo, leptin seems to chiefly control body weight and not inflammatory or hematopoietic processes.
Agnello
D
D
"Mario Negri" Institute for Pharmacological Research, 20157 Milan, Italy.
Meazza
C
C
Rowan
C G
CG
Villa
P
P
Ghezzi
P
P
Senaldi
G
G
D000818:Animals; D003345:Corticosterone / Q000097:blood; D004357:Drug Synergism; D005260:Female; D006131:Growth Inhibitors / Q000494:pharmacology; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis / Q000502:physiology*; D020738:Leptin; D053605:Leukemia Inhibitory Factor; D007958:Leukocyte Count; D008070:Lipopolysaccharides / Q000494:pharmacology; D008222:Lymphokines / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D011506:Proteins / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000494:pharmacology; D000685:Serum Amyloid A Protein / Q000096:biosynthesis; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D015431:Weight Loss / Q000187:drug effects*
D006131:Growth Inhibitors; D007375:Interleukin-1; D015850:Interleukin-6; C507837:LIF protein, human; D020738:Leptin; D053605:Leukemia Inhibitory Factor; C507838:Lif protein, mouse; D008070:Lipopolysaccharides; D008222:Lymphokines; D011506:Proteins; D011994:Recombinant Proteins; D000685:Serum Amyloid A Protein; D014409:Tumor Necrosis Factor-alpha; D003345:Corticosterone