Metabolism of tiaramide in vitro II. Oxidation of piperazineethanol group in tiaramide by 105 000 g supernatants from monkey and rat liver

Abstract

1. The piperazineethanol group in tiaramide was metabolized to the corresponding piperazineacetic acid group by monkey- and rat-liver preparations.

2. Formation of the piperazineacetic acid by soluble fractions from monkey and rat livers was faster with NAD⁺ than with NADP⁺ and was inhibited by pyrazole and disulfiram.

3. Tiaramide treatment did not impair ethanol elimination from blood of rats, but pyrazole pretreatment caused a drastic decrease of the piperazineacetic acid metabolite in the liver and serum of rats treated with tiaramide.

4. These results, and studies on partially purified liver enzymes, indicate that in monkey and rat liver, oxidation of the piperazineethanol moiety in tiaramide to piperazineacetic acid is catalysed by alcohol and aldehyde dehydrogenase.