THE METABOLISM OF C¹⁴ 2-PAM IN THE ISOLATED PERFUSED RAT LIVER. II. 2-O-CONJUGATE PYRIDINIUM ION

¹ Department of Pharmacology and Toxicology, The University of Wisconsin Medical School, Madison, Wisconsin

Biotransformation of carbon-14 labeled 2-PAM was investigated in the isolated perfused rat liver. The isolation and characterization of a metabolite of 2-PAM were described. Properties of the metabolite were found to be consistent with those of a 2-O-conjugate pyridinium ion.

Isolation of the metabolite was accomplished by the following procedures: ethanol extraction of the liver perfusate; adsorption of the metabolite on a charcoal-celite column and subsequent elution with ethanol; further fractionation by use of ion exchange and paper chromatography and, finally, purification by paper electrophoresis.

The 1-methyl-2-ethoxypyridinium iodide was prepared as an example of a 2-O-conjugate pyridinium ion in order to facilitate the identification of the metabolite. Characterization of the metabolite was accomplished by comparing the chemical, spectrophotometric, chromatographic and electrophoretic properties of the metabolite, before and after alkaline hydrolysis, with 1-methyl-2-pyridone and 1-methyl-2-ethoxy-pyridinium iodide. The nature of the 2-O-conjugate was investigated and discussed.