In contrast to the reports by Riddle et al. (25), we did not observe any changes in the hepatic mRNA or protein levels of PERK, ATF4, or GRP78 in IUGR foetuses, possibly because we analysed different tissues or from different rat models (uteroplacental insufficiency-induced) and different developmental stages in our study. This evidence concerns the gene EIF2AK3 and fetal growth restriction.