The phytoestrogen genistein induces thymic and immune changes: A human health concern?

摘要: Use of soy-based infant formulas and soy/isoflavone supplements has aroused concern because potential estrogenic effects the soy isoflavones genistein daidzein. Here we show that s.c. injections in ovariectomized adult mice produced dose-responsive decreases thymic weight up to 80%. Genistein's occurred through both estrogen receptor (ER) non-ER-mediated mechanisms, as on thymus were only partially blocked by ER antagonist ICI 182,780. Genistein decreased thymocyte numbers 86% doubled apoptosis, indicating mechanism effect loss thymocytes is caused part increased apoptosis. injection relative percentages CD4(+)CD8(-) double-positive CD4(+)CD8(+) thymocytes, providing evidence may affect early maturation helper T cell lineage. Decreases accompanied splenic cells a systemic lymphocytopenia. In addition, suppression humoral immunity. injected at 8 mg/kg per day serum levels comparable those reported soy-fed human infants, this dose significant immune changes mice. Critically, dietary concentrations substantially less than infants marked atrophy. These results raise possibility found be capable producing abnormalities, suggested previous reports impairments infants.