Treatment with PEG-IGF-I resulted in a decrease in infarct volume when treatment started at 3 hrs post-stroke but not when started at either 1 or 5-days post-stroke (vehicle, 1.26 ± 0.11 mm3 versus 1 mg/kg PEG-IGF-I (3 hrs), 0.91 ± 0.06 mm3, P < 0.05; 1-day, 1.19 ± 0.08 mm3, P = 0.6600; 5-day, 1.16 ± 0.31 mm3, P = 0.7736: n = 6 per group; Fig. 2C). This evidence concerns the gene IGF1 and Stroke.