Soy sterols in the regulation of thyroid functions, glucose homeostasis and hepatic lipid peroxidation in mice

The potential of phytosterols, isolated from soy beans in the alterations of thyroid function, glucose metabolism and hepatic lipid peroxidation was evaluated in adult mice. Dual effects were observed with two different concentrations of soy sterols. Its administration at 5.0 mg/kg for 21 days significantly increased the serum thyroxine and insulin levels, but reduced the levels of serum triiodothyronine and glucose; activities of hepatic 5′monodeiodinase and glucose-6-phophatase as well as lipid peroxidation, with a concomitant increase in superoxide dismutase, catalase and reduced glutathione, exhibiting hypothyroid and glucose lowering properties. Most of these effects were comparable to that of a standard antithyroid drug, propylthiouracil. However, administration of 10.0 mg/kg of soy sterol significantly enhanced serum glucose and hepatic lipid peroxidation. Findings suggest that soy sterols, at a moderate concentration potentially ameliorates hyperthyroidism and diabetes mellitus, but at higher concentration it may exert adverse effects.