Cardiac hypertrophy is determined by an increase of cell size in cardiomyocytes (CMCs). Among the cellular processes regulating the growth of cell size, the increase of protein synthesis rate represents a critical event. Most of translational factors promoting protein synthesis stimulate cardiac hypes-trophy. In contrast, activity of translational repressor factors, in cardiac hypertrophy, is not fully determined yet. Here we report the effect of a translational modulator, eIF6/p27(BBP) in the hypertrophy of neonatal rat CMCs. The increase of eIF6 levels surprisingly prevent the growth of cell size induced by phenylephrine, through a block of protein synthesis without affecting skeletal rearrangement and ANF mRNA expression. Thus, this work uncovers a new translational cardiac regulator independent by other well-known factors such as mTOR signalling or eIF20. (C) 2017 Elsevier Inc. All rights reserved.