Figure 1.

Thymic effects of genistein. (A) Thymic weights in 100-day-old ovariectomized mice given 21 daily s.c. injections with DMSO, E₂ (5 μg/kg), or genistein (2–200 mg/kg). Some mice given E₂ or 200 mg/kg genistein were also given weekly injections (5 mg/week) of the antiestrogen ICI 182,780. Genistein produced dose-dependent decreases in thymic weights, which exceeded those seen with E₂ at higher genistein doses. ICI 182,780 only partially blocked genistein effects, indicating that genistein acts partly through a non-ER mechanism. Data are presented as mean ± SE; n ≥ 7 for all groups. Columns with different superscript letters are statistically different. (B) Whole-mount photographs of individual thymic lobes from mice treated as in A.