In vivo phosphorus nuclear magnetic resonance (31P-NMR) study of dystrophic hamster muscle.

Skeletal muscle bioenergetics of dystrophic hamsters (DH) were studied by in vivo 31P-NMR in order to evaluate possible metabolic impairment. 31P-NMR data were obtained during rest, during muscle work that was induced by nerve stimulation at 3 frequencies (0.2, 0.4 and 1.0 Hz) and during postexercise recovery. At rest, phosphocreatine-to-inorganic phosphate ratio (PCr/Pi) was significantly (P less than 0.02) lower in adult DH (5.3 +/- 1.1; +/- 2 SD) compared with control hamsters (6.55 +/- 0.5). An increased PCr depletion was found in DH muscle during nerve stimulation and the steady-state PCr/Pi was significantly (P less than 0.05) lower at 0.4 and 1.0 Hz. Slow PCr/Pi recovery was observed in DH (0.5 +/- 0.2 units per min compared with 1.42 +/- 0.28 for control, +/- 2 SD, P less than 0.02). These findings suggest a significant in vivo mitochondrial malfunction in DH muscle that may result from either mitochondrial abnormalities or cardiac insufficiency or a combination of both.