TABLE 2.

Fold Changes in Antioxidant Enzyme Activities in Mammary and Tumor Tissue in the E₂ and E₂ + BHA-Exposed Group

	SOD		CAT		GPx
Treatment Group	E2	E2 + BHA	E2	E2 + BHA	E2	E2 + BHA
7 days	0.9 ± 0.3	0.8 ± 0.2	1.0 ± 0.1†	0.6 ± 0.04*	1.5 ± 0.3	1.0 ± 0.2
15 days	1.1 ± 0.3	1.1 ± 0.3	1.1 ± 0.2	0.7 ± 0.09	1.1 ± 0.3	1.2 ± 0.6
120 days	1.5 ± 0.2	1.2 ± 0.2	0.9 ± 0.1†	0.6 ± 0.03	1.0 ± 0.2	0.8 ± 0.1
240 days	3.1 ± 0.8*,†	0.8 ± 0.2	1.2 ± 0.1†	0.6 ± 0.06	1.4 ± 0.2	0.4 ± 0.2
Tumor	1.8 ± 0.4*	0.8 ± 0.1	0.7 ± 0.1	0.7 ± 0.2	2.5 ± 0.4*	0.9 ± 0.2

The activity of the antioxidant enzymes SOD, CAT, and GPx were measured in mammary tissue from animals in the control, BHA, E₂ and E₂ + BHA groups. Quantification of enzyme activity was performed on mammary tissue from animals in each group after 7, 15, 120, and 240 days of exposure as described in the Methods section. Enzyme activity was measured in mammary tumor tissue as well. Fold changes were calculated for E₂ and E₂+ BHA group relative to respective age-matched controls. Data are reported as an average of values obtained from at least eight different animals ± SE except in E₂ + BHA-treated tumor group in which only four animals had tumor.

^*Indicates a significant difference (p < 0.05) compared to respective controls, whereas

^†indicates the significant difference (p < 0.05) between E₂ and E₂ + BHA-treated groups.