COMPARATIVE-STUDIES ON TRYPTOPHAN BINDING TO HEPATIC NUCLEAR ENVELOPES IN SPRAGUE-DAWLEY AND LEWIS RATS

Since Lewis rats are susceptible to many inflammatory diseases and hav e been used in an experimental model of the eosinophilia-myalgia syndr ome, we investigated whether Lewis rats would respond to L-tryptophan as have Sprague-Dawley rats reported earlier. In this comparative stud y using females of both strains, we observed a decrease in the affinit y of in vitro L-tryptophan binding to hepatic nuclei and nuclear envel opes of Lewis rats compared with Sprague-Dawley rats. However, in vivo stimulatory effects of administering L-tryptophan on hepatic polyribo somal aggregation, protein synthesis, and nuclear RNA release were sim ilar in both strains. In vitro [H-3]tryptophan binding to hepatic nucl ear envelopes, using L-tryptophan implicated in cases of the eosinophi lia-myalgia syndrome, revealed less specific binding than when using n onimplicated L-tryptophan in both strains. The possible significance o f the quantitative difference in the binding affinity of L-tryptophan to hepatic nuclei of Lewis rats compared with those of Sprague-Dawley rats is as yet undetermined.