Meeting Abstract

P2.130  Friday, Jan. 4  Activities of antioxidant enzymes and membrane susceptibility to lipid peroxidation in skeletal muscle from temperature-acclimated bluegill (Lepomis macrochirus) MILES, DRB*; GRIM, JM; CROCKETT, EL; Ohio University; Ohio University; Ohio University dm359002@ohio.edu

With temperature variation, poikilotherms remodel membrane lipids by making adjustments in phospholipid composition in order to protect membrane physical properties and function. Two common features of phospholipid remodeling involve modifications in the amount of polyunsaturated fatty acids and relative levels of various phospholipid classes. These changes, coupled with increased oxidative capacity at cold body temperatures, may affect the membrane�s susceptibility to lipid peroxidation (LPO) and therefore require increased antioxidant defenses. Oxidative capacity and antioxidant enzyme activity, along with membrane susceptibility to LPO, were studied in glycolytic muscle of bluegill Lepomis macrochirus acclimated to 5°C or 25°C for 8 weeks. Rates of LPO were quantified in microsomal membranes using thiobarbituric acid reactive substances (TBARS) and C11-BODIPY, a fluorescent lipophilic reporter. Oxidative capacity was determined from the activity of cytochrome c oxidase (CCO), and activities of superoxide dismutase (SOD) and catalase (CAT) represented the antioxidant response. Although oxidative capacity increases by 1.7-fold in cold-acclimated fish, neither LPO susceptibility (as indicated by both methods used) nor antioxidant responses differ significantly between temperature treatments. Support from Ohio University Provost�s Undergraduate Research Fund to DRBM and Ohio University Research Committee to ELC.