Fig. 4. (A ) The effect of oral administration of l-NAME (L) and 10 μg/kg intravenous infusion of endotoxin (E) on urinary levels of nitrite plus nitrate (NO²⁻+ NO³⁻). Urine samples were obtained before l-NAME on day 6, after l-NAME but before endotoxin on day 12, and after endotoxin on days 15 and 19 of pregnancy. l-NAME resulted in decrease in urinary NO²⁻+ NO³⁻levels in the pregnant positive control group (PL) and the group of pregnant rats that were administered oral l-NAME starting on day 7 and then a single 10-μg/kg endotoxin infusion on day 14 of pregnancy (PLE). Endotoxin infusion in the PLE group resulted in reversal of that effect and significant increase in the urinary NO²⁻+ NO³⁻levels. (B ) The effect of oral administration of l-NAME and 10-μg/kg intravenous infusion of endotoxin on urinary protein levels. l-NAME resulted in significant proteinuria, which was augmented by endotoxin infusion. *P < 0.05. PC = pregnant negative control group.