The activity of IRPs in skeletal muscle is not altered during high-altitude exposure. RNA bandshift analysis of IRPs activity in muscle biopsies obtained from vastus lateralis under normoxic conditions at SL and during exposure to HA (4559 m) for 7 to 9 days. Cytosolic extracts were incubated with an excess of a 32P-labeled IRE probe, and the RNA-protein complexes were separated on nondenaturing polyacrylamide gels. (A) A typical bandshift representative of 1 experiment performed with extracts of the 9 participants of the present study. (B) Quantification of IRP binding activity obtained from 3 independent determinations and expressed relative to the value at SL, which was arbitrarily defined as 100. The values are means ± SE for 9 participants.
