1. 1. Vitellogenin synthesis was induced in liver of salmon ( Salmo salar) by injecting 17-β-estradiol. 2. 2. Liver nuclei were isolated and incubated with micrococcal nuclease. The chromatin was fractionated into a 3000 g pellet, a 100,000 g pellet and supernatant fraction. The chromatin fractions were extracted stepwise with 0.35 and 2 M NaCl. 3. 3. As analyzed by PAGE, histone HI together with a few non-histone proteins decreased after induction while the high mobility group proteins T and C increased. 4. 4. Anion-exchange HPLC revealed a high number of different proteins. Upon induction some of the proteins present in the 0.35 M NaCl extract of the controls shifted to the 2 M NaCl extract suggesting an increase in the binding of the proteins to DNA. 5. 5. The results obtained provide the basis for further studies on the isolation of proteins of relevance to the modulation of gene activity.