CONTRACTILE PROTEIN GENE-EXPRESSION IN SERUM-FREE CULTURED ADULT-RAT CARDIAC MYOCYTES

The effects of two adhesion substrates (serum and laminin) and time in culture on the expression of genes encoding myosin heavy chain (MHC) isoforms and alpha-skeletal actin were analysed in myocytes isolated f rom adult rat heart and maintained in serum-free culture. Relative mes senger ribonucleic acid (mRNA) abundances were quantitated by dot-blot analysis. Gene expression was not influenced by the substrate used. T ime in culture induced a decrease in total mRNA abundance and an up-re gulation of beta-MHC and alpha-skeletal actin genes. It is proposed th at atrophy of adult myocytes is associated with a pattern of gene expr ession similar to the fetal program.