Plasma and muscle carnitine in experimental uremia

The effect of uremia and dietary protein intake on carnitine levels in skeletal muscle and plasma of rats was evaluated. Male Sprague-Dawley rats weighing 160–180 g were made chronically uremic by partial ligation of left renal artery and contralateral nephrectomy. Rats were fed diets containing 8% or 18% casein ad libitum for 8 weeks and sham-operated pair-fed animals were used as controls. At the end of the experiment, all animals were fasted overnight and decapitated. Skeletal muscle and plasma were assayed for free, total acid-soluble and long-chain acylcarnitines. The concentration of total carnitines in skeletal muscle were similar in uremic and control rats fed either 8% or 18% casein diet. However, the muscle long chain acylcarnitines were higher in rats fed the 18% casein diet than those fed the 8% casein diet. Diets (8% or 18% casein) had no effect on the plasma carnitine level, although uremic rats had lower levels than the controls. This study has shown that kidney dysfunction may affect the plasma carnitines level but not the total skeletal muscle carnitines concentration.