AJP - Regulatory, Integrative and Comparative Physiology, Vol 250, Issue 5 776-R782, Copyright © 1986 by American Physiological Society
Rat endogenous pyrogen and fever
A. Morimoto, T. Watanabe, T. Ono, Y. Sakata and N. Murakami
Rat endogenous pyrogen (EP), prepared from the white blood cells of
lipopolysaccharide-pretreated rats, produced a fever in both rabbits and
rats. The effects of human, rabbit, and rat EP on the body temperatures of
rabbits and rats were investigated to clarify differences in the febrile
response to each kind of EP. The latency to fever onset and the time to
peak fever induced by rat EP in rabbits and rats were significantly greater
than those induced by human and rabbit EP. The maximum elevation of the
body temperature induced by rat EP in both animals was almost identical to
that induced by human and rabbit EP. In a comparison of the febrile
responses to various EPs between rabbits and rats, the latency to fever
onset, the time to peak, and the maximum elevation of fever in rats were
approximately half those observed for rabbits. Furthermore, the threshold
dosage to induce a fever response in rats was greater than that necessary
for rabbits. It is concluded that rat EP could be obtained by in vitro
techniques and that rats have the physiological mechanisms to develop a
fever through production of EP.
