Decrease of 3-methylhistidine and increase of NG,NG-dimethylarginine in the urine of patients with muscular dystrophy.

The amounts of 3-methylhistidine, N epsilon,N epsilon-dimethyllysine, N epsilon, N epsilon, N epsilon-trimethyllysine, NG,NG-dimethylarginine, and NG,N'G-dimethylarginine were determined in the urine specimens of healthy subjects and patients of corresponding ages with Duchenne, limb-girdle, and congenital types of muscular dystrophy, and motor neuron diseases. The amount of excretion of 3-methylhistidine decreased and that of NG,NG-dimethylarginine increased significantly in Duchenne and limb-girdle types of muscular dystrophy, but not in diseases with neurogenic muscular atrophy. The decrease of 3-methylhistidine was observed consistently throughout the course of the Duchenne type of muscular dystrophy. The amounts of the other methylamino acids both in myogenic and neurogenic myopathies were not different from those in healthy subjects.