Does glucose 6-phosphatase regulate metabolic transformation in developing skeletal muscle?

Glycogen content and the activities of phosphorylase, phosphohexose isomerase, aldolase, glucose 6-phosphatase, succinate dehydrogenase, and alanine and aspartate amino-transferases have been biochemically determined in three gastrocnemii muscles of chick up to 9 weeks of postembryonic growth. Decline in glycogen, phosphorylase, phosphohexose isomerase and aldolase with a concomitant increase in succinate dehydrogenase reveals a switchover from glycolytic to oxidative metabolism in muscle. Activities of aminotransferases indicate the utilization of transamination products of alanine and aspartate in oxidative pathway. Transiently increased glucose 6-phosphatase seems to restrict glycogenolytic and glycolytic metabolism and thereby pave way for the acceleration of oxidative metabolism in developing muscle.