ELEVATED NADPH-OXIDASE ACTIVITY IN NEUTROPHILS FROM BILE-DUCT-LIGATEDRATS - CHANGES IN THE KINETIC-PARAMETERS AND IN THE OXIDASE CYTOSOLICFACTOR P47

Stimulated superoxide generation was 2-fold higher in neutrophils from 20 rats with common bile-duct ligation (CBDL) compared to that of 20 sham-operated control rats. In order to study the mechanism of the hig her NADPH oxidase activity in CBDL rats, the kinetic parameters of NAD PH oxidase were analyzed. The V-max of the NADPH oxidase in CBDL rat n eutrophils was significantly higher than that of control rat neutrophi ls (10.2 and 5.3 nmol/min, respectively). The membrane and cytosol fra ctions of the oxidase were studied in a cell-free system. Neutrophil c ytosol from CBDL rats added to neutrophil membranes from either CBDL o r control rats produced 22.4 +/- 1.6 and 21.0 +/- 1.4 nmol/10(6) cells per 10 min, respectively. When neutrophil cytosol from control rats w as mixed with neutrophil membranes from control or CBDL rats the gener ation of superoxide was 10.6 +/- 1.4 and 10.0 +/- 1.5 nmol/10(6) cells per 10 min, respectively. These results suggest that the cytosol comp onents of the oxidase regulate its activity. By immunoblot analysis it was shown that the amount of the cytosolic factor p47 in neutrophils of CBDL rats is higher than that present in an equal number of neutrop hils from control rats.