Gender Dimorphism in the Exercise‐naïve Murine Skeletal Muscle Proteome

Abstract

Skeletal muscle is a plastic tissue with known gender dimorphism, especially at the metabolic level. A proteomic comparison of male (n=5) and female (n=5) murine (C57BL/10ScSnJ000476 +/+) biceps brachii was undertaken, resolving an average of 600 protein spots of MW 15–150 kDa and pI 5–8. 24 unique full‐length proteins spanning 11 KOG groups demonstrated statistically significant (p<.05) abundance differences between genders; the majority of these proteins have metabolic functions. Identified glycolytic enzymes demonstrated decreased abundance in females, while identified oxidative phosphorylation enzyme abundance differences were specific to the proteins rather than to the function group as a whole. Myoglobin and GRP78 showed the largest abundance increases of 3.9 and 5.8‐fold, respectively, whereas dihydrolipoamide S‐succinyltransferase showed the largest decrease of 5.9‐fold in the females. All three phosphorylation states of creatine kinase were decreased in females. Expression differences were significant but many subtle, usually 2‐fold or less. We conclude that while gender dimorphism is present in non‐exercised murine skeletal muscle, the proteome comparison of male and female biceps brachii in exercise‐naïve mice does not indicate any apparent hormonal regulatory basis for the dimorphism. Supported by NSF 0420971, the Smith College Blakeslee Fund and HHMI.