Effect of IGF-I transgene on size and weight of mouse brain. Representative H&E-stained sagittal sections of the brain from Ptc1+/+ (A) and Ptc1+/-/IGF-I Tg mice (B) of 8 weeks of age, showing a large increase in brain size due to the combination of IGF-I transgene and Ptc1 heterozygous mutation. Bar = 5.0 mm. (C) Graphic representation of brain weights at 3, 5 and 8 weeks of age. (D) The presence of IGF-I transgene produced significant increase of brain weights both in Ptc1+/+ and Ptc1+/-mice.