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January 1974

Adenyl Cyclase in Normal and Pathologic Human Muscle

Author Affiliations

From the Spiller Neurological Unit and the Clinical Research Center, Hospital of the University of Pennsylvania, Philadelphia.

Arch Neurol. 1974;30(1):96-102. doi:10.1001/archneur.1974.00490310098016

Adenyl cyclase activity in normal human muscle is stimulated four to seven times by epinephrine and about 18 times by sodium fluoride. The enzyme is present in all particulate fractions of muscle (myofibrils, mitochondria, sarcoplasmic reticulum) but not in the soluble phase. The highest specific activity is found in isolated plasma membrane.

Basal enzyme activity was normal in muscle from patients with Duchenne or facioscapulohumeral dystrophy but the response to epinephrine was about 30% of normal and the response to sodium fluoride about half normal. In polymyositis, responses were normal, and intermediate values were found in myotonic dystrophy. In denervated muscle, responses were enhanced. In fetal muscle there was no response to epinephrine but sodium fluoride stimulated, suggesting that the mechanisms of these agents differ.

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