Comparison of xylitol and glucose metabolism in nonhepatic rat tissues

Capability and extent of xylitol metabolism in vitro was studied in a variety of non-hepatic tissues of rats, using enzymatic and isotopic methods. Only kidney was found to be able to utilize xylitol at a significant rate while in all other organs tested - lung, brain, heart muscle, skeletal muscle and adipose tissue - no uptake of xylitol was detectable using two independent methods. In accordance with these results the incorporation of radioactivity from [U-14C]-xylitol as substrate into the products CO2 and lactate was found to be very small in all organs with the exception of kidney and when compared to that from [U-14C]-glucose it was less than 5%. From these results it is concluded that besides liver only kidney can utilize xylitol to a significant extent while for the other tissues studied xylitol is not a suitable substrate.