Peptide chain initiation and analysis of in vitro translation products in rat heart undergoing hypertrophic growth.

The cytosol fraction of rat heart contains an initiation factor-like protein component that behaves like the eukaryotic factor (eIF-2) in binding [35S]-Met-tRNAf in the presence of GTP. The ternary initiator complex thus formed is able to bind to heart ribosomes. In the left ventricle of rat heart undergoing hypertrophic growth upon constriction of the descending aorta, the [35S]-Met-tRNAf binding activity of the cytosol protein(s) gradually increases after the operation from 40%, at 48 h, to 90%, at 10 days; slightly lower activation is seen in the [35S]-Met-tRNAf binding to ribosomes. Polysomal RNA is extracted from sham operated and hypertrophic rat hearts and translated in a reticulocyte cell free system. The translation products are analyzed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis: no clearcut qualitative difference is observed in the pattern obtained from sham operated and hypertrophic animals.