Aim: To further explore the molecular mechanism of antipyretic action of Guizhi Tang

the differences on the protein expression in hypothalamus of fever rats induced by yeast were analyzed preliminarily. Methods: Both the quantitative and qualitative changes of the protein expression in hypothalamus were compared between the model group and treated group with Guizhi Tang using two-dimensional polyacrylamide gel electrophoresis. Results: There are obvious differences in expression of some proteins with a percentage of 2.3% among distinguishable spots. They changed mostly in volume and rarely in isoelectric point

of which

eight proteins (Mr/pI:28.9 kD/4.47

24.4 kD/6.28

25.4 kD/6.39

25.9 kD/6.39

17.6 kD/7.38

17.2 kD/7.43

24.9 kD/7.39

26.9 kD/7.59) enhanced in abundance

six proteins(Mr/pI:14.3 kD/4.83

28.5 kD/4.39

16.2 kD/4.11

15.3 kD/6.7

30.5 kD/7.09

30.5 kD/7.13)showed lower expression and one (Mr/pI:14.8 kD/5.4) changed in isoelectric point. There was no unmatched protein spot. Conclusions: The changes in expression level and modification of some proteins may contribute to the antipyretic action of Guizhi Tang.