AJP - Cell Physiology, Vol 232, Issue 1 15-C22, Copyright © 1977 by American Physiological Society
Differentiation between endogenous pyrogen and leukocytic endogenous mediator
C. A. Mapes and P. Z. Sobocinski
The crude material released from glycogen-stimulated rabbit peritoneal
polymorphonuclear leukocytes when administered to experimental animals
elicits a number of metabolic and physiologic alterations characteristic of
those observed in the host inflammatory response. Classically, the mediator
of febrile response observed in rabbits and other species has been termed
endogenous pyrogen (EP), whereas leukocytic endogenous mediator (LEM) has
been used as a general term to denote the substance(s) mediating multiple
inflammatory responses observed in rats. The latter substance, however, has
not been previously demonstrated to differ from EP. This report presents
evidence indicating that EP and LEM are different molecular species.
Evidence supporting the differentiation between these entities includes:
physical separation of EP from one or more mediators that induce metabolic
alterations attributed to LEM; production of LEM activities by stimulated
polymorphonuclear leukocytes in the absence of detectable pyrogenic
activity; and differences in the release of EP and LEM from stimulated
rabbit granulocytes in the presence of potassium ion.
