Table 4

Effect of 3-methylcholanthrene (MC) pretreatment on the concentration of DMBA and its metabolites in tissues of rats given [3H]DMBA

In experiments 1 and 2, rats pregnant for 15 days were injected i.p. with 5 mg of MC at 24 h before the oral administration of 20 mg of [3H]DMBA, and the rats were killed 2 or 4 h later. Pregnant rats were used in experiments 1 and 2 to obtain sufficient mammary tissue for analysis. In experiment 3, nonpregnant female rats were injected i.p. with 5 mg of MC at 24 h before the oral administration of 20 mg of [3H]DMBA, and the rats were killed 2 h later. Total radioactivity was determined in the various tissues. Each value represents the average and SE from 5 rats per group. More detailed studies indicated that pretreatment of the rats with MC before administration of DMBA decreased the concentration of DMBA and its hydroxymethyl metabolites in the adrenal gland and fat (see text). (Taken from Ref. 36 .)

ExperimentTissueTreatmentHours after DMBA administrationHydrocarbon (nmol/gm tissue)
1AdrenalCorn oil251.0 ± 3.4
AdrenalMC21.1 ± 1.4
MammaryCorn oil219.5 ± 2.0
MammaryMC7.3 ± 0.8
2AdrenalCorn oil461.4 ± 5.2
AdrenalMC17.8 ± 1.0
MammaryCorn oil463.4 ± 7.3
MammaryMC8.8 ± 0.6
3AdrenalCorn oil266.4 ± 4.8
AdrenalMC24.3 ± 3.2
FatCorn oil236.2 ± 4.1
FatMC10.7 ± 2.2