Influence of daily ethanol injection on compensatory hypertrophy in the rat

Abstract

Acute ethanol exposure inhibits muscle protein synthesis, while chronic ethanol exposure causes muscle wasting in humans and laboratory animals. In contrast, resistance exercise increases muscle protein synthesis and thus muscle mass, but few studies have addressed the interaction of ethanol and exercise. To assess this interaction, we removed the right gastrocnemius from Sprague‐Dawley rats (n=23) and then injected the animals with ethanol (75 mmol/kg) or an equivalent volume of saline daily for 3 weeks. Surgically overloaded plantaris muscles were 85% larger than muscles from contralateral control legs in saline‐treated animals and 94% larger than contralateral controls in ethanol‐treated animals. The relative mass of the non‐surgical plantaris was not significantly different in saline‐ and ethanol‐treated animals (0.85 ± 0.02 g/kg for ethanol vs. 0.89 ± 0.03 g/kg for saline, p=0.10). Ethanol also had no effect on relative mass of the overloaded plantaris (1.67 ± 0.09 g/kg for ethanol vs. 1.65 ± 0.06 g/kg for saline, p=0.81). These results indicate that a single daily dose of ethanol is unable to prevent overload‐induced hypertrophy in skeletal muscle. This work was sponsored by the Department of the Navy, Office of Naval Research, under Award # N00014‐11‐1‐0359.