Neutrophil function during pregnancy: is nitric oxide production correlated with superoxide production?

Oxygen radical formation by neutrophils during pregnancy is not well studied.

We studied neutrophil-derived superoxide anion (O) and nitric oxide (NO) values in 75 normal pregnant women, 12 postpartum women, and 10 non-pregnant women. O production was measured by the superoxide dismutase-inhibitable reduction of ferricytochrome c. NO production was measured by accumulation of the stable end product nitrite using a modified Griess reaction method.

O production of neutrophils stimulated by chemotactic peptide was significantly enhanced in the early second trimester of pregnancy. l-arginine analogue-inhibitable nitrite production was induced in neutrophils from pregnant women, but not from postpartum and non-pregnant subjects. In third-trimester subjects but not non-pregnant subjects, neutrophils pre-treated with l-arginine analogues enhanced O production compared with untreated neutrophils.

These findings indicate that O and NO production by neutrophils during pregnancy were modulated separately, whereas neutrophil-derived NO might function as a regulator of O.