Metabolic Disposition of β-Aminopropionitrile in the Rat 1 2

Abstract

Summary

Enzymatic conversion of the lathyrogen, β-aminopropionitrile (BAPN) to the deaminated, nonlathyrogenic metabolite, cyanoacetic acid (CAA) by rat liver homogenates was found to be less than 1%. Urine of rats injected with 400 mg/kg of BAPN ip contained 32% unchanged BAPN in 24 hr, with negligible recovery thereafter. BAPN-derived CAA showed 12 and 22% recovery in the urine in 24 and 48 hr, respectively. These data suggest that significant amounts of unchanged BAPN may not exist in rat tissues after 24 hr, and that BAPN-derived CAA in such tissues is gradually excreted. The observation that radioactivity in rat brain and liver 24 hr after [¹⁴C]BAPN injection is present exclusively as [¹⁴C]CAA supports this interpretation.