Changes in serum glucocorticoid levels and thymic atrophy induced by phenytoin administration in mice

The weights of spleen and thymus were recorded and serum glucocorticoid (GC) levels examined in mice injected intraperitoneally with 60 mg phenytoin (PHT) kg body wt. for 3, 8, and 30 days. In mice injected with PHT, the serum GCs were elevated about 4- to 5-fold in 3 days; the higher levels were maintained and accompanied thymic atrophy throughout the experiment. Moreover, dose-dependent changes in serum GC levels and thymus weight were also observed at 3 days. These results indicate that GCs may play an important role in thymic atrophy induced by PHT.