CAMP and cGMP changes associated with the differentiation of cultured chick embryo muscle cells

Abstract

Changes in the intracellular concentration of cAMP and cGMP were examined in primary cultures of chick embryo skeletal muscle cells. The reciprocal changes, increase in cAMP and decrease in cGMP level, were observed during the early stage of myogenesis. Consequently, the ratio of cAMP to cGMP increased significantly during that period reaching the maximum level on day 3. The most marked change in the nucleotide ratio, an approx. 2-fold increase, was observed between the 2nd and 3rd day of culture which coincided with the period of cell fusion. After the 3rd day, the value of nucleotide ratio remained constant throughout the period examined. These findings pose the possibility that the intracellular levels of both cyclic nucleotides are involved in the regulation in myoblast differentiation.