Mitochondrial myopathy in rats fed with a diet containing beta-guanidine propionic acid, an inhibitor of creatine entry in muscle cells.

In rats with phosphoryl-creatine depletion (fed a standard Randoin-Causeret diet containing 1% beta-guanidine propionic acid) abnormal mitochondria were observed in slow skeletal muscles, often containing paracrystalline inclusions very like those induced by ischaemia or mitochondrial poisons and in human mitochondrial myopathy.