The Effects of Dioscorea bulbifera L. on Hyperthyroidism of Rats

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Objective: The aim was to study experimentally the effects of Dioscorea bulbifera L. induced by sodium levothyroxine. Methods: Sprague-Dawley rats were separated into four groups. Except for the normal group, the other three were treated with sodium levothyroxine $160{\mu}g/kg$ for 5 days. Among the three groups, two (except the control) were treated with Dioscorea bulbifera L. extract of 0.75g/kg (sample A) or 1.5g/kg (sample B). $T_3-uptake,\;T_3,\;T_4$, TSH, total cholesterol, glucose, ALP, AST, ALT, tree fatty acids, $\beta-lipoprotein$, and change in the serum of rats were measured after medication with solid extract of Radix Scrophulariae. Results: $T_4$ concentration and $T_3-uptake$ level decreased in sample A and B compared to controls. $T_3$ concentration decreased but not statistically meaningful. Considering lipid metabolism, only free fatty acid level was significantly reduced glucose level also significantly decreased in sample B. Serum AST, ALT and ALP levels were slightly elevated but there was no meaning statistically, which doesn't mean Dioscorea bulbifera L. has liver toxicity because the quantity of the extract perhaps couldn't reach the minimal dose causing liver toxicity, which according to an article was 60g. Body weight significantly increased in comparison to controls. Conclusion: These results suggest that Dioscorea bulbiftra L. lowers excess thyroid hormone and increased metabolism, resulting in improvement of hyperthyroid state.