Mutant Rats Resist Warfarin

Simone Rost from the University of Wuerzburg, Germany, and an international team of researchers studied more than 250 rats and mice from anticoagulant-exposed areas in Europe, East Asia, South Africa and the Americas. Rost explained that, "Resistance against warfarin-like compounds has been reported in rodent populations from many countries around the world and poses a considerable problem for efficacy of pest control."

Warfarin and related compounds are derivatives of the plant toxin coumarin. They prevent blood coagulation by repressing the enzyme vitamin-K reductase (VKOR). Rost and colleagues studied VKORC1, the gene responsible for a key component of the VKOR multiprotein complex. According to the authors, "Mutations in VKORC1 may cause a heritable resistance to warfarin, possibly by preventing coumarin derivatives from interfering with the activity of the reductase enzyme".