Lactate transport activity in rat skeletal muscle sarcolemmal vesicles after acute exhaustive exercise

Laboratoire de Physiologie des Interactions, Service Central de Physiologie Clinique, Hôpital A de Villeneuve, 34295 Montpellier cedex 5, France The effect of a single bout of exhaustive exercise on muscle lactate transport capacity was studied in rat skeletal muscle sarcolemmal (SL) vesicles. Rats were assigned to a control (C) group ( n = 14) or an acutely exercised (E) group ( n = 20). Exercise consisted of treadmill running (25 m/min, 10% grade) to exhaustion. SL vesicles purified from C and E rats were sealed because of sensitivity to osmotic forces. The time course of 1 mM lactate uptake in zero- trans conditions showed that the equilibrium level in the E group was significantly lower than in the C group ( P