Effect of a myocardial volume overload on lactate transport in skeletal muscle sarcolemmal vesicles

1 Department of Health and Human Performance, Auburn University and 2 Department of Anatomy, Physiology, and Pharmacology, Auburn University College of Veterinary Medicine, Auburn, Alabama 36849; and 3 Department of Human Nutrition, Foods, and Exercise Science, Virginia Tech, Blacksburg, Virginia 24061 This study sought to determine the effect of a myocardial volume overload (MVO) on sarcolemmal (SL) lactate (La ) transport and the aerobic profile of skeletal muscle. SL vesicles were obtained from female rats 10 wk after either a MVO was induced by creation of an infrarenal fistula ( n = 10), or sham surgeries were performed ( n = 11). Influx of 14 C-labeled L(+)-La was measured at various unlabeled La concentrations under zero- trans conditions. La transport kinetics were determined using a Michaelis-Menten equation with an added linear component to discriminate between carrier-mediated and diffusional transport. Although heart and lung weights were significantly increased ( P