Status of nitric oxide free radicals in diabetic neutrophils: effect of diabetic serum factor on the generation of these species in normal neutrophils and their relation to lysosomal degranulation.

Normal polymorphonuclear leukocytes (PMNL) in contrast to diabetic PMNL, generated significant amounts of .NO and NO2 when challenged with opsonised zymosan. Diabetic neutrophils, on the other hand, responded either weakly or insignificantly to the same stimulants. However, in resting state the levels of .NO and NO2 were higher in diabetic as compared to normal PMNL. Diabetic serum factor (DSF) provoked a significant generation of .NO and NO2 in normal PMNL, a phenomenon found parallel to the enhancement in cytosolic cathepsin D activity in normal cells on insult with DSF.

Plausible involvement of a diabetic serum factor in neutrophil membrane pathology.

With a view to determining the role of diabetic serum factor (DSF) in the progression of membrane pathology, time-dependent preincubation effects of DSF on certain membrane-bound enzymes of normal polymorphonuclear leucocytes (PMNL) have been studied. DSF is found to cause significant decrements in the activities of Na+/K+ ATPase, PLC and AcE of PMNL on in vitro incubation for 60 min, while the effect on Ca2+/Mg2+ ATPase appears only on prolonged incubation with an initial hike in activity at 5 min. The implications of these results have been discussed.