Interaction of Hepatic Chromatin with Androgen-Receptor Complex

Summary

When the chromatin prepared from male rat livers interacted with [³H] testosterone-receptor complex prepared from male rat livers, the binding was much higher than when interacted with free [³H] testosterone, indicating that the formation of testosterone-receptor complex is prerequisite for interaction with chromatin. When the [³H] testosterone-receptor complex was interacted with the chromatin and the bound chromatin proteins were extracted into three fractions based on their extractability or solubility in salt solutions, higher radioactivities were found in the 0.35 M NaCl-extract and 2.0 M NaCl residual fraction. Chromatin was fractionated into 0.35 M NaCl-soluble, 2.0 M NaCl-soluble and insoluble fractions, and interaction of free [³H] testosterone or [³H] testosterone-receptor complex with chromosomal fractions was studied. The binding of the chromosomal fractions with free [³H] testosterone was negligible compared with that of [³H] testosterone-receptor complex. The binding of 0.35 M NaCl-soluble fraction with [³H] testosterone-receptor complex was higher than that of 2.0 M NaCl-soluble fraction. The binding ability of 2.0 M NaCl-insoluble fraction with [³H] testosterone-receptor complex was twice as much as that of the intact chromatin. This observation indicated that salt-soluble fractions of chromatin contributes only partly to the binding of chromatin with [³H] testosterone-receptor complex and that other components in 2.0 M NaCl-insoluble fraction may participate in the binding.

Key words

Androgen receptor - Chromatin - Rat liver - Nuclear matrix