Fig. 2. Heart rate during the 60-min study period. Pooled mean heart rate in groups breathing 6% oxygen was significantly greater than that in groups breathing 30% oxygen ( P < 0.01). Administration of 0.02 ml/g HRC 101 attenuated the hypoxia-induced increase in heart rate. Data are mean ± SD. Alb = albumin; SAD = transgenic mice expressing hemoglobin SAD; WT = wild-type.