ACCUMULATION OF 1-METHYL-TETRAHYDRO-BETA-CARBOLINE-3-CARBOXYLIC ACID IN BLOOD AND ORGANS OF RAT - A POSSIBLE CAUSATIVE SUBSTANCE OF EOSINOPHILIA-MYALGIA-SYNDROME ASSOCIATED WITH INGESTION OF L-TRYPTOPHAN

1-Methyl-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) may cause eosinophilia-myalgia syndrome (EMS) associated with ingestion of L-try ptophan. The distribution and excretion of MTCA were studied in rats w hich had received perorally a single 1.6 mg/kg dose of MTCA. MTCA conc entrations in blood, kidney, liver, brain, heart, spleen, lung and gas trocnemius muscle were measured by HPLC combined with fluorometric det ection. The concentration of MTCA in each organ reached a maximum at 1 h and then gradually declined. However, a significant level of MTCA s till remained at 5 h, when 52% of ingested MTCA remained in the conten ts of the large intestine. Twenty-nine percent of the ingested MTCA wa s excreted in urine over the course of 24 h. A higher dose (10 mg/kg) of MTCA resulted in significant elevations in the concentrations and a mounts of MTCA in the various organs. In addition, chronic treatment w ith a 10 mg/kg dose of MTCA for 6 weeks further increased the concentr ations and amounts of MTCA in each organ. However, no histological cha nges were observed in any of the organs after chronic treatment. This is the first report which demonstrates accumulation of MTCA in the blo od and various organs, including muscle, of rats.