Ventilatory responses before and after hyperoxia, and during recovery. Minute ventilation (VE) in response to decreasing levels of inspired O2. In each one of the three conditions, mean values (± SD) of VE in IGF-1R+/+ and IGF-1Rneo/- mice were recorded under 90% O2, 21% O2 and at two levels of hypoxia (12% and 10% O2). Values with asterisks are significantly different from control values at 90% O2. Crosses indicate significant differences from normoxic control values, and asterisks indicate significant differences between IGF-1R+/+ and IGF-1Rneo/- mice; P < 0.05.