Bleomycin (BLM), a DNA-cleaving, antitumor antibiotic, causes pulmonary fibrosis. It also causes cell injury and activates the nuclear enzyme poly(ADP-ribose) polymerase (PAP; EC 2. 4. 2 VSports手机版. 30) in lung slices exposed to the drug in vitro. 3-Aminobenzamide (3-AB), a PAP inhibitor, prevents enzyme activation and cell injury. We have examined the potential role of ATP and NAD depletion in injury of BLM-sensitive C57B1/6N and -resistant BALB/cN murine lung slices treated with BLM or deprived of glucose, the major metabolic substrate of lung. Lung slices either were treated for 45 min with injurious concentrations of BLM (10-500 micrograms/mL) or were incubated without glucose, in the presence or absence of 2. 5 mM 3-AB. Only the highest concentration of BLM, 500 micrograms/mL, caused any ATP depletion, and this 35% decrease was transient, occurring at 220 min in C57B1/6N slices. In contrast, glucose deprivation caused 50-70% ATP depletion in slices from both strains. BLM alone at 100 and 500 micrograms/mL caused a sustained 30-70% NAD depletion from 75 min through 400 min in C57B1/6N mouse lung slices. In the resistant BALB/cN lung slices, NAD depletion by BLM was only seen at 400 min. 3-AB almost completely antagonized NAD depletion in slices from both strains. In contrast to BLM, glucose deprivation did not decrease NAD levels unless 3-AB was present in C57B1/6N slices. Thus, ATP depletion may play a role in the injurious effects of glucose deprivation, but does not appear to be a major factor in pneumocyte injury caused by BLM. NAD depletion or other effects of PAP activation appear to account for the strain-selective, injurious effect of BLM on lung tissue. .