EDN1 and fetal growth restriction: In the present study, an IUGR rat model induced by maternal nutrient restriction was used to investigate the level of histone acetylation and DNA methylation of ET-1 gene promoter region in lung tissues from 1-day-old and 10-week-old IUGR rats, and the reactivity of IUGR rats to ovalbumin (OVA) allergen challenge was assessed.