Heat shock factor activation in human muscles following a demanding intermittent exercise protocol is attenuated with hyperthermia.
OBJECTIVE
The present study investigated whether increased activation of heat shock factors (HSF) following exercise relates primarily to the increased muscle temperature or to exercise in general.


METHODS
Six subjects completed 40 min of intermittent cycling (15s:15s exercise:recovery at 300 +/- 22 W) at an ambient temperature of either 20.0 +/- 1.3 or 40.3 +/- 0.7 degrees C. Muscle biopsies were taken prior to and immediately following the exercise protocol with samples analysed for HSF DNA binding by electrophoretic mobility shift assay.


RESULTS
Exercise at 40 degrees C resulted in significantly increased oesophageal (39.3 +/- 0.2 degrees C) and muscle temperature (40.0 +/- 0.2 degrees C) at the end of the exercise protocol compared with 20 degrees C (oesophageal, 38.1 +/- 0.1 degrees C; muscle, 38.9 +/- 0.2 degrees C). However, an increased DNA binding of HSF was not evident following exercise at 40 degrees C (reduced by 21 +/- 22%) whereas it increased by 29 +/- 51% following exercise at 20 degrees C.


CONCLUSIONS
It appears that increased temperature is not the major factor responsible for activation of HSF DNA binding.
Palomero
J
J
Division of Metabolic and Cellular Medicine, School of Clinical Sciences, University of Liverpool, Liverpool, UK.
Broome
C S
CS
Rasmussen
P
P
Mohr
M
M
Nielsen
B
B
Nybo
L
L
McArdle
A
A
Drust
B
B
D000328:Adult; D001642:Bicycling / Q000502:physiology; D001831:Body Temperature / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D004947:Esophagus / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response / Q000502:physiology; D006801:Humans; D006979:Hyperthermia, Induced; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D013696:Temperature
D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins