Alterations in metabolism of cytidine components in rat liver after oral administration of butylated hydroxytoluene (in vivo study).

The administration of the antioxidant, butylated hydroxytoluene (BHT) to rats decreased the utilization of [2-14C]orotic acid for the synthesis of cytidine nucleotides in the acid-soluble extract and RNA of the liver. The specific activity of the uridine components was slightly decreased. The depression of the specific activity of the cytidine components depended on the dose of the drug. Simultaneously preformed [U-14C]cytidine in experimental rats was to a higher degree transported to the liver and incorporated into RNA cytosine; its deamination was markedly suppressed. Both phenomena depend on the BHT dose. The concentration of both the uridine and the cytidine components of the acid-soluble extract remained unaffected by the administration of BHT. The utilization of [2-14C]orotic acid for the synthesis of DNA cytosine was depressed after the administration of BHT; by contrast, the specific activity of DNA thymine was higher. The incorporation of [1-14C]palmitic acid into microsomal phospholipids was not substantially influenced over the dose range 25--500 mg BHT/kg. The specific activity of neutral lipids in microsomes increased.