Urinary excretion products after the administration of 14C-acetaldehyde to rats.

Rats were injected with 120 micro Ci of 14C-acetaldehyde containing carrier acetaldehyde, and the urinary excretion products were assayed by cation exchange chromatography, resolving five main peaks of radioactivity. Urine contained 6% of the dose of 14C-acetaldehyde administered. The main urinary product of acetaldehyde, fraction 5, was produced via acetate. Acetate was also identified in the urine. Two cysteine adducts, probably isomeric metabolites of 2-methylthiazolidine-4-carboxylic acid, were detected. They constituted about 2% of the radioactivity in the urine collected 48 h after the administration of 14C-acetaldehyde. They appeared to retain a carboxylic group. When the reaction mixture of 14C-cysteine and acetaldehyde was injected into a rat, the half-lives of the two tiazolidine derivatives was 10 h. Only 13.6% of the radioactivity was detected in the urine suggesting ready metabolism of 2-methylthiazolidine-4-carboxylic acid.