Circadian Variation in Host Defense

摘要

The circadian rhythm in body temperature is thought to be due to a rhythm in the thermoregulatory set-point . The overall goal of the authors research was to determine whether this represents a circadian fever. If this hypothesis is correct, then antipyretic drugs should attenuate the rhythm in body temperature. The authors have found that administration of a variety of antipyretic drugs to rats markedly reduced their nighttime elevation in body temperature. These data suggest to us that prostaglandins are probably involved in the circadian rhythm in body temperature. The authors have attempted to determine whether this rhythm in prostaglandins is dependent on a rhythm in circulating concentrations of interleukin-1 (IL-1). Based on studies with rats and human beings using bioassays and immunoassays, the authors have been unable to detect any rhythm in plasma concentration of IL-1. The authors conclude that it is unlikely that circulating IL-1 has a role in the rhythm in body temperature. If IL-1 influences the circadian rhythm in body temperature, it may do so at the level of the hypothalamus or at some other central nervous site.