Metabolic fate and mechanism of action of chloroethylthiamine. II. Movement and fate of chloroethylthiamine along intestinal lumen after oral administration to chick.

The route of arrival of chloroethylthiamine at the cecal site after oral administration to chick was examined, as the drug is particularly active against Eimeria tenella which is parasitic in the cecal tissue. Macroautoradiography of chick whole gastrointestinal tract and the assay of radioactivity of various parts of the tract periodically after oral administration of 35S-chloroethylthiamine indicated that chloroethylthiamine arrives and accumulates at the cecal site mainly by the passage through the digestive tract, in the highest concentration at about 8 hr after administration. It was found that when administered into the ligated duodenal loop only a slight radioactivity was distributed in the cecal tissue. In addition, the most of radioactivity orally administered was found to be excreted into the urine during the first 5 hr with the maximum rate between 2 and 4 hr, indicating that the urinary backflow is not participating in the accumulation in the ceca.