Ultrastructural demonstration of glucose-6-phosphatase activity and glycogen in skeletal muscles of newborn piglets with the splayleg syndrome.

The ultrastructural localization of glucose-6-phosphatase activity and glycogen were investigated in the longissimus dorsi and biceps femoris muscles of normal and splaylegged newborn piglets. Significant differences were ascertained in the distribution of the reaction product of glucose-6-phosphatase activity between the two groups of animals. A fine precipitate was found in the sarcoplasmic reticulum and in the perinuclear cisternae of normal piglet muscles. In splaylegged muscles, variable deposits of coarse reaction product were observed within the extremely dilated cisternae of sarcoplasmic reticulum at their periphery. Moreover, both longitudinal and transversal ultrathin sections of these muscles showed a reduced number of myofibrils and an increased accumulation of glycogen (especially within the large extramyofibrillar spaces) in comparison with muscles of normal piglets.