Temporal changes in glycogenolytic enzyme mRNAs during myogenesis of primary porcine satellite cells

The objective was to study the regulation of glycogenolytic enzyme mRNAs in porcine satellite cells during proliferation and differentiation. Beyond 80% confluence, cells were grown in absence or presence of 1 μM insulin. The observed increases in abundance of mRNA for glycogenin, glycogen synthase, phosphorylase kinase, phosphorylase and glycogen debranching enzyme, and no alterations of the transporter molecule GLUT4, clearly indicate that glycogenolytic enzymes of potential importance to meat quality development are regulated at the gene level during myogenesis, and are heavily involved in muscle cell and muscle fibre development. The genes, however, are not influenced by insulin, and the lack of response to insulin of expression of gene-encoding enzymes involved in the formation and degradation of glycogen may question the applicability of porcine cell culture systems, like the one applied, as a model to study the regulation and regulatory mechanism of energy metabolism in muscles.