Figure 4. Aminoguanidine decreases release of nitrite and nitrate into the perfusate of lungs obtained from rats treated with LPS. Rats were pretreated with an intraperitoneal injection of 0.5 mg/kg LPS (n = 12) or were untreated control rats (n = 9). Four hours later, seven of the LPS-treated rats and four of the control rats received an intraperitoneal injection of aminoguanidine (AG; 30 mg/kg). After 12–14 h, the lungs were isolated and perfused, and perfusate samples were taken after 30 min of perfusion. Compared with LPS-treated rats without aminoguanidine, the combined nitrite and nitrate levels were less in the perfusate of lungs from LPS-treated rats given aminoguanidine (*P < 0.05 values differ).