The effect of epinephrine and other glycogenolytic agents on the phosphorylase A content of muscle

Chronic Progressive Myopathy With Myoglobinuria: Demonstration of a Glycogenolytic Defect in the Muscle*

“…On the other hand, addition of crystalline phosphorylase greatly increased lactate formation (Table IV). This finding and the demonstrated absence of phosphorylase activity, even in the presence of epinephrine or adenylic acid (26,50) (Table V). indicated that the primary defect involved the phosphorylase system.…”

“…In vitro, lactate production by the patient's muscle was greatly reduced in spite of the presence of increased amounts of glycogen. This defect was not corrected by preincubation of muscle tissue with epinephrine (26,50), nor by addition of glycogen prepared from normal human muscle or from rat muscle. On the other hand, addition of crystalline phosphorylase greatly increased lactate formation (Table IV).…”

“…In normal muscle that has been exercised (26,50) or totally immobilized (Table V), phosphorylase may be largely present in its metabolically R2LTI) SCHMID AN1) ROBERT MAHLER inactive formi "bl,"' but coniversion to the enzymiiatically active form "a" can be achieved by epineplhrine (26,50). This is illtustrated in Table V where preincubationi of normiial rectus muscle witlh epinephrinie resulted in significantly increased phosphorylase activity.…”

“…\Vith the patient's muscle, on the otlher lhand, these compounds did not inicrease enzymilatic activity. Fuirthermiiore, the patient's mluscle dlid nlot appear to conitain phosphorylase inhibitors or increased activity of the phosphorylase-rupturing enzyme (50,51), since the muscle honmogeniate from the patient did not reduce the enzymatic activity of niormal lutiscle preparations (Table V).…”

The Effect of Physostigmine on Heart Phosphorylase Activity in the Spinal Rat

“…The isolated heart was frozen in a mixture of alcohol-dry ice, and phosphorylase determination was made according to the method of Cori and Illingworth (10). The detail of the procedures was described previously (1).…”