The Metabolism of Oxoquinolizidines in Rabbits

Abstract

1. After administration of 1-, 2- and 3-oxoquinolizidines to rabbits, the urine contained the corresponding alcohols, with cis and trans isomers occurring in the thermodynamically expected ratio. Occasionally, the urinary content of glucuronic acid was raised.

2. 4-Oxo-[4-¹⁴C]quinolizidine did not undergo reduction of the oxo-group. Instead, scission of the C-N bond occurred to give a mixture of acids, thought to be piperidine-2-butyric acid and 6-oxopiperidine-2-butyric acid, which were excreted in the urine in conjugated form.

3. The in vivo reduction of 1-, 2- and 3-oxoquinolizidine was reproducible in vitro using a sol. liver fraction which was not alcohol dehydrogenase, and by aromatic aldehyde-ketone reductase.