THE COMPARATIVE METABOLISM OF DIISOPROPYL METHYLPHOSPHONATE IN MINK AND RATS

This study reports the metabolism of carbon-(14)labeled diisopropyl me thylphosphonate (DIMP) in mink and rats, undertaken to better understa nd the dose-related mortality reported for mink in a previous study. I n both male and female mink and rats, DIMP was rapidly absorbed after oral administration; it was metabolized by a saturable pathway to a si ngle metabolite, isopropyl methylphosphonate (IMPA), which was rapidly excreted, primarily in the urine (90%). Fecal radioactivity, also ide ntified as IMPA, was 1.7-3.1% of the administered dose. Female rats ha d a slower rate of conversion of DIMP to IMPA and less total excretion of IMPA than male rats. Metabolism of DIMP administered intravenously was not very different from that given orally in both species. These data indicate that mink absorb, metabolize, and excrete DIMP (as IMPA) in a manner very similar to mice, rats, and dogs.