Elucidation of the rapid in vivo metabolism of arecoline

1. The metabolism of arecoline (ARE) was examined in homogenates of mouse blood, brain, kidney, and liver tissue. 2. Liver and kidney tissues exhibited the greatest rates of ARE metabolism. 3. The specific carboxylesterase inhibitor TOCP (tri-o-tolyl-phosphate) as well as ISO-OMPA (tetraisopropyl-pyrophosphoramide) completely blocked ARE metabolism in liver homogenate. 4. ISO-OMPA significantly inhibited ARE metabolism by purified porcine liver carboxylesterase. 5. The data suggest that carboxylesterase (EC 3.1.1.1) is primarily responsible for the metabolism of ARE in the mouse.