Journal of Applied Physiology, Vol 51, Issue 1 62-67, Copyright © 1981 by American Physiological Society
Prostaglandin E1 hyperthermia: effects on ability to work in the heat
R. Francesconi and M. Mager
To assess the effects of preinduced hyperthermia on the ability to exercise
in the heat, prostaglandin E1 (PGE1) was administered
intracerebroventricularly to male rats weighing 275-350 g. Following
injection of PGE1, a fever of 2 degrees developed within 20-30 min, at
which time a 1-ml blood sample was taken. When these animals exercised in
the heat (37 degrees C) to hyperthermic exhaustion (42.5-43 degrees C),
their endurance capacity was significantly reduced (P less than 0.001) when
compared with controls. Exercise to hyperthermic exhaustion resulted in
significantly (P less than 0.05, minimal) increased plasma levels of
lactate, potassium, and urea nitrogen in both control animals and those
receiving PGE1. However, PGE1 pretreatment did not exacerbate these
increments. Plasma glucose and sodium levels were significantly (P less
than 0.05) increased in PGE1-treated animals, whereas glucose levels were
reduced significantly (P less than 0.05) in both groups postrun. We
concluded that preinduced hyperthermia severely reduces the ability to work
in the heat. Although the clinical chemical indices of heat injury are
unaffected by PGE1 pretreatment, the effects of PGE1 administration on
circulating levels of glucose and sodium require further study.
