Formation of N-nitrosodimethylamine by NOx exposure in rats and rabbit pretreated with aminopyrine.

Nitrosodimethylamine (NDMA) was detected in the blood, liver and lungs of rats and in the blood of a rabbit, when the animals had been administered aminopyrine and subsequently exposed to nitrogen dioxide in air. The control group not administered aminopyrine (AP) showed no significant amount of NDMA. Dose-effect relationships between the nitrogen dioxide level and the concentration of NDMA produced in the blood, liver and lungs of the rat were confirmed. NDMA was not produced in rats administered AP alone. The rates of NDMA production and disappearance in the blood of the rabbit administered AP and exposed to NO2 were so high that the steady-state level of NDMA in the blood was relatively low. When a rat administered AP was exposed to NO, no significant amount of NDMA was detected in the animal.