title: Metabolic responses to interleukin-1: centrally and peripherally mediated.
abstract: OBJECTIVE
  The purpose of this study was to differentiate between the catabolic effects of interleukin-1 (IL-1) when infused into the central nervous system or into the periphery.
  
  
  BACKGROUND
  After injury and infection, IL-1 has been found in the central nervous system. Chronic intracerebrovascular infusion of IL-1 produces protein catabolism, anorexia, and fever. However, IL-1 may act directly on liver and bone marrow to elicit metabolic responses. Although IL-1 is thought to be involved in a number of metabolic responses associated with injury-inflammation, the sites of action are unclear.
  
  
  METHODS
  Rats were implanted with chronic infusion pumps and received diluent or three doses of IL-1 infused subcutaneously for 6 days, and a variety of response variables were measured. In a second study, doses were adjusted so that similar systemic catabolic responses were obtained from peripheral and intracerebroventricular infusion of IL-1. The acute-phase responses then were compared in the two groups of animals receiving IL-1 by different routes.
  
  
  RESULTS
  Subcutaneously infused IL-1 elicited catabolic responses in a dose-response manner. Similar catabolic responses were achieved by infusing one tenth of the dose of IL-1 given subcutaneously into the central nervous system. Although similar systemic responses (protein catabolism, anorexia, fever, and weight loss) were observed with both routes of infusion, the subcutaneous infusion produced a much greater lymphocytosis, elevation in acute-phase reactants, and fall in serum iron and albumin.
  
  
  CONCLUSIONS
  The IL-1 appears to have different effects depending on the site of production and site of action. Regionalization of signal proteins such as IL-1 should be taken into consideration when devising specific anticytokine treatment strategies.
authors.affiliation: Department of Surgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: A G
authors.initials: AG
authors.lastname: Hill
authors.forename: J
authors.initials: J
authors.lastname: Siegel
authors.forename: J
authors.initials: J
authors.lastname: Rounds
authors.forename: D W
authors.initials: DW
authors.lastname: Wilmore
mesh_terms: D000818:Animals; D002490:Central Nervous System / Q000378:metabolism*; D007279:Injections, Subcutaneous; D007375:Interleukin-1 / Q000008:administration & dosage / Q000378:metabolism*; D017933:Peripheral Nervous System / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D007375:Interleukin-1