Intracerebroventricular Administration of Leukocytic Endogenous Mediators (LEM) in the Rat

Abstract

LEM obtained from glycogen-induced peritoneal exudates in rabbits were injected into the lateral cerebral ventricle (icv) of rats to determine if LEM had a primary site of action in the CNS. LEM injected icv in the dose of 10, 20 or 50 .mu.l produced a rapid hyperthermia. Injection of heated LEM failed to cause a hyperthermic response. Endotoxin and heated endotoxin (20 ng/20 .mu.l/rat) administered icv each produced a delayed hyperthermia as compared to LEM. The various doses of LEM also significantly decreased plasma Fe and Zn, increased plasma Cu, increased the synthesis of plasma .alpha.2 acute-phase protein (.alpha.2-MFP), and caused a flux of a nonmetabolizable amino acid ([14C]AIB [.alpha.-amino-isobutyric acid]) to the liver. LEM, in doses which are inactive systemically, can apparently mediate certain effects on or through the CNS following icv administration.