Effect of retinol on macromolecular synthesis in cultured cell lines

The effects of retinol on SK Mel 28 and HeLa cell lines were studied with regard to DNA and protein synthesis. It was found that vitamin A added to the culture media at a 50 microM concentration causes a 60% inhibition of DNA synthesis, that the inhibition is reversible and that this treatment does not select retinol-resistant clones. The synthesis of cytoplasmic, acid-soluble nuclear proteins and that of non-histone chromosomal proteins is inhibited as soon as the vitamin reaches the cell.