IGF1 and fetal growth restriction: Consistent with the growth and organ weight data, suppressed genes resulting from IUGR status included growth regulators, such as IGF1. Ferenc and colleagues also detected differences between IUGR and normal piglets at day 7 of age related to metabolism and found a reduction of hepatocyte numbers together with significant modifications of expression of key hormones and enzymes for protein and carbohydrate metabolism in IUGR neonates.