Inhibition of triiodothyronine production by fenugreek seed extract in mice and rats

The effects of fenugreek seed extract on the alterations in serum thyroid h ormone concentrations were studied in adult male mice and rats. Simultaneou sly, hepatic lipid peroxidation (LPO) and the activities of the antioxidant enzymes, viz superoxide dismutase (SOD) and catalase (CAT) were examined. Administration of methi seed extract (0.11 g kg body wt.(-1) day(-1) for 15 days) to both mice and rats significantly decreases serum triiodothyronine (T-3) concentration and T-3/T-4 ratio, but increases thyroxine (T-4) level s and body weight. While hepatic LPO and CAT activities were not altered, a significant decrease in SOD activity was observed in both the animal model s. These findings suggest that fenugreek seed extract induced inhibition in T-4 to T-3 conversion is not peroxidation-mediated and the inhibition in S OD activity could be the result of a decrease in the protein anabolic hormo ne, T-3. (C) 1999 Academic Press.