Creatine kinase release from isolated EDL muscles in chronic ethanol-treated rats

Chronic ethanol abuse has been shown to cause damage to skeletal muscle in animals and patients as reflected by elevated serum levels of cytosolic enzymes and histological examination. The present study investigated the hypothesis that elevated serum creatine kinase levels in ethanol-treated animals vs. sucrose control animals may result from increased enzyme release or efflux from muscle. Creatine kinase release was measured from extensor digitorum longus (EDL) muscles isolated from rats chronically treated for 28 weeks with ethanol and from sucrose fed controls. The in vitro cumulative release of creatine kinase over a 2-h period was significantly higher in the ethanol-treated animals. Consistent with an increased release of enzyme into the bath, creatine kinase levels in muscle homogenates at the end of the incubation period were lower in the ethanol-treated animals. Creatine kinase levels in serum obtained from trunk blood samples were statistically higher in the ethanol-treated animals compared to sucrose controls. These findings demonstrate increased enzyme release from fast-twitch skeletal muscle in chronic ethanol-treated rats.