Figure 1.

The time-course of total protein binding in vivo of 1-NN metabolites was quantified in rat airway epithelium (left) and liver (right) after exposure to 50 mg/kg ¹⁴C-1-NN. Each diamond represents an individual animal, and each horizontal line represents the average value of that time-point (n = 2). The maximum protein binding occurred as early as 2 h after injection in the airway epithelium compared with ∼ 6 h after injection in the liver. The extent of binding was, on average, 4-fold higher in the airway than in the liver.