Hepatic microsomal N-hydroxylation of p-chloroaniline and p-chloro-N-methylaniline in red-winged blackbird compared with rat.

1. N-Hydroxylation of p-chloroaniline (PCA) and p-chloro-N-methylaniline (PCMA) was measured in red-winged blackbird (Agelaius phoeniceus) and rat (Rattus norvegicus) hepatic microsomes. 2. Redwing hepatic microsomes N-hydroxylated PCA slower than rat microsomes. Furthermore, redwing hepatic microsomes had marginal or no ability to N-hydroxylate PCMA, whereas rat hepatic microsomes N-hydroxylated PCMA at a higher rate than PCA. 3. The bird hepatic microsomes had only low or marginal N-demethylase activity with PCMA, whereas the rat hepatic microsomes could N-demethylate PCMA at a higher rate than they could N-hydroxylate it.