AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 2 552-R557, Copyright © 1990 by American Physiological Society
Effect of gastrointestinal flora on body temperature of rats and mice
M. J. Kluger, C. A. Conn, B. Franklin, R. Freter and G. D. Abrams
Department of Physiology, University of Michigan Medical School, Ann Arbor 48109.
The purpose of these experiments was to test the hypothesis that gut flora
influences the body temperature of rodents. Rats and mice were implanted
with biotelemetry transmitters that enabled us to record both abdominal
temperature and activity for long periods of time. Rats given nonabsorbable
antibiotics in their drinking water, which reduced their gut flora, had a
marked decrease in both their daytime and nighttime temperatures. Similar
results were found with germfree mice. The circadian rhythms in body
temperature of germfree and conventionalized mice were not different.
However, the body temperatures of the germfree mice were lower than those
of the conventionalized mice during both the daytime and nighttime. The
decrease in body temperature in the germfree mice was not related to
changes in activity. These results support the hypothesis that gut flora
has a tonic stimulatory effect on both the daytime and nighttime body
temperature of rodents.
