EXCRETION OF MALONDIALDEHYDE, FORMALDEHYDE, ACETALDEHYDE, ACETONE ANDMETHYL ETHYL KETONE IN THE URINE OF RATS GIVEN AN ACUTE DOSE OF MALONDIALDEHYDE

A high pressure liquid chromatographic system (HPLC) has recently been developed for the simultaneous detection of malondialdehyde (MDA), fo rmaldehyde (FA), acetaldehyde (ACT) and acetone (ACON). We have examin ed the urinary excretion of these four lipid metabolites in the urine of rats following the acute oral administration of MDA, (158 mg/kg bod y weight). During the first 12 h, increases in the urinary excretion o f MDA and ACT of approximately 192- and 70-fold, respectively, were ob served. The urinary excretion of both MDA and ACT decreased thereafter . An increase in FA excretion was observed only 12-24 h after MDA admi nistration. A significant decrease in ACON relative to control values was observed 12-48 h after MDA treatment. Two new peaks were present i n the HPLC chromatograms of urine samples 0-24 h after MDA administrat ion. Both peaks were shown to be due to methyl ethyl ketone (MEK) whic h appears to be formed as a result of MDA metabolism. The results demo nstrate that orally administered MDA is rapidly excreted in the urine, and alters the metabolism and excretion of other lipid metabolites.