Recovery of lung pyridine nucleotides following acute exposure of adult and aged rats to ozone.
Male, pathogen-free Fischer 344 rats aged 6 and 24 mo were exposed to 1.5 or 3.0 ppm for 8 h and recovery rates of diphosphonucleotides (NAD+ and NADH) and triphosphonucleotides (NADP+ and NADPH) were measured and compared to controls. Recovery after 0.5 ppm was not examined because no significant changes occurred in either age group after this lower exposure. At zero time (immediately after exposures) both concentrations are depressed in adults and aged animals except for NADH in aged animals at 3.0 ppm; NADP+ in adults at 1.5 and 3.0 ppm was decreased, but not significantly. For NAD+ and NADH, recovery of whole lung concentrations is complete by 24 h following an 8-h exposure to 1.5 or 3.0 ppm of ozone. Only after 3.0 ppm of ozone was the ratio of the reduced to oxidized form (NADH/NAD+) still elevated after 24 h; however, it also returned to control levels by 96 h. For the triphosphonucleotides, an 8-h exposure to 1.5 ppm of ozone resulted in a sustained depression of whole lung concentrations of NADPH throughout the 96-h recovery period. Also, only after the 1.5 ppm exposure was the reduced to oxidized ratio (NADPH/NADP+) significantly depressed throughout the 96-h recovery period. Unexpectedly, recovery of whole lung levels returned to normal within 24 h after the 8-h exposure to both the 1.5 and the 3.0 ppm concentrations. With the exception of the sustained effect on NADPH levels, these data indicate that di- and triphosphonucleotide concentrations rapidly return to normal in the lung after severe, acute oxidant injury. There were no differences in recovery rates between the adult and the aged groups.
Montgomery
M R
MR
College of Public Health, University of South Florida, Tampa.
Raska-Emery
P
P
Balis
J U
JU
D000375:Aging / Q000378:metabolism*; D000818:Animals; D008168:Lung / Q000737:chemistry / Q000187:drug effects*; D008297:Male; D009243:NAD / Q000032:analysis*; D009249:NADP / Q000032:analysis*; D010084:Oxidation-Reduction; D010126:Ozone / Q000633:toxicity*; D051381:Rats; D011916:Rats, Inbred F344; D013047:Specific Pathogen-Free Organisms
D009243:NAD; D009249:NADP; D010126:Ozone