The metabolism of cyclic-3'-5'-adenosine monophosphate (cAMP) in diseased muscle.

Adenyl cyclase (AC) and cyclic nucleotide phosphodiesterase (PDE) have been studied in muscle from patients affected with muscular and neuromuscular diseases as well as in muscle of rats after experimental denervation. A diminution of AC was observed in Duchenne's dystrophy, in neurogenic atrophies, in inflammatory forms, in myasthenia and myotonia. PDE was diminished in Duchenne's dystrophy and increased in all other diseases considered. Both enzymes were increased in rat muscle after nerve transection. The possible mechanism underlying the biochemical alterations observed are discussed including unmasking of extra-activity due to changed metabolic environment, tissue destruction and activation of lysosomal activity.