Effect of a lipid load on blood and urinary carnitine in man.

Blood and urine carnitine contents have been determined in patients before and after a lipid load and in patients on haemodialysis. Oral and intravenous lipid administration significantly depressed blood carnitine content and after 500 ml intravenous Intralipid urinary carnitine excretion fell by 43%. Blood carnitine was reduced by 50% by haemodialysis and returned to the pre-dialysis value within 20 h in 5 out of 8 patients. It is concluded that the blood carnitine level is normally controlled over a narrow range. The fall in blood carnitine concentration and urine excretion which follows a lipid load indicate a limiting role for carnitine in lipid utilization in man, and suggest that carnitine supplements could be of value during parenteral nutrition with fats.