1,3-DINITROBENZENE METABOLISM AND TOXICITY IN SEMINIFEROUS TUBULES ISOLATED FROM RATS OF DIFFERENT AGES

Previous in vivo studies in rats have shown that susceptibility to 1,3 -dinitrobenzene (DNB)-induced testicular damage increases with age. Th e present study has used an in vitro approach to investigate the possi bility that differences in testicular metabolism contribute to the age -related differences in toxicity. Seminiferous tubules were isolated f rom Sprague-Dawley rats (30, 75 and 120 days old) and incubated with 1 00 mu M DNB for 22 h. Formation of metabolites and tubular levels of A TP and glutathione (GSH) were monitored over time. There was no differ ence in seminiferous tubule metabolic capacity among the three ages of rats examined. After 22 h of incubation with DNB, ATP levels were 20- 30% of control and GSH levels were 70-90% of control, but neither para meter showed an age-related difference in decline. Based on these bioc hemical indicators of cell health, this study would suggest that the l ack of testicular toxicity in young animals in vivo may be due to the previously described shorter half-life with consequent reduced exposur e of the testis to DNB and that the age-related increase in severity o f lesion between 75 and 120 days of age cannot be explained by differe nces in tubular metabolism of DNB or whole-animal toxicokinetics. (C) 1997 Elsevier Science Ireland Ltd.