CARNITINE-ACYLCARNITINE TRANSLOCASE ACTIVITY IN CARDIAC MITOCHONDRIA FROM AGED RATS - THE EFFECT OF ACETYL-L-CARNITINE

Age-related changes in mitochondrial fatty acids metabolism may underl ie the progressive decline in cardiac function. The effect of aging an d acute treatment with acetyl-L-carnitine on fatty acids oxidation and on carnitine-acylcarnitine translocase activity in rat heart mitochon dria was studied. Rates of palmitoylcarnitine supported respiration as well as carnitine-carnitine and carnitine-palmitoylcarnitine exchange reactions were all depressed (approx. 35%) in heart mitochondria from aged rats. These effects were almost completely reversed following tr eatment of aged rats with acetyl-L-carnitine. Heart mitochondrial card iolipin content was significantly reduced (approx. 38%) in aged rats. Treatment of aged rats with acetyl-L-carnitine restored the level of c ardiolipin to that of young rats. It is suggested that acetyl-L-carnit ine is able to reverse age-related decrement in mitochondrial carnitin e-acylcarnitine exchange activity by restoring the normal cardiolipin content.