Our results showed that the expression levels of p-PERK, p-elf2, and ATF-4 were all enhanced after IH treatment; however, the expression levels of p-IRE1 and active ATF-6 were not elevated, suggesting that the IRE1 and ATF6 pathways are probably not involved in this process. This evidence concerns the gene EIF2AK3 and isolated hemihyperplasia.