Retronecine acts as the better competitor for the competitive inhibition of antibodies to Retronecine.

In this investigation, the in-vitro and in-vivo metabolic activation of Retronecine was studied. Rat liver microsomal metabolism of Retronecine in the presence of calf thymus DNA resulted in the formation of a set of DHP-DNA adducts. The metabolism of Retronecine N-oxide under similar conditions also formed the similar set of DHP-DNA adducts. The level of DNA adducts from Retronecine was enhanced when metabolism by liver microsomes from phenobarbital (PB)-induced rats were used. The DHP-DNA adducts were also found in the liver DNA of female F344 rats treated with Retronecine or Retronecine N-oxide. The highest level of the total DHP-DNA adducts was found in liver DNA from the rats treated with dehydroRetronecine (DHR). The order of the levels of DNA adducts in the liver DNA samples from rats treated with various pyrrolizidine alkaloids was: DHR > riddelliine > riddelliine N-oxide >> Retronecine > Retronecine N-oxide.