Androgen-stimulated labelling of chromosomal proteins by isolated prostate nuclei

Although the biochemical role of amino acid incorporation into proteins catalysed by isolated nuclei is obscure, description of any changes that follow altered cellular function may aid in its definition. The following observations were obtained with ventral prostate nuclei from rats deficient in, or stimulated by androgen. 1. 1. Labelling of nuclear proteins, measured in intact animals or with incubated nuclei, was partially androgen-dependent. Under both conditions, non-histone (acidic) proteins were highly labelled. 2. 2. Nuclei from castrated rats treated with androgen for 24–72 h were increasingly active, depending upon the length of exposure to the hormone. 3. 3. Response to the hormone was specific for the target organ, while administration of cyproterone acetate, a powerful anti-androgen, inhibited incorporation by isolated prostate nuclei. 4. 4. On neutral SDS-polyacrylamide gels, the distribution of in vitro-labelled nuclear proteins from hormone-stimulated rats exhibited many similarities, and some differences, compared with castrates. 5. 5. The presence in incubated mince and incubated nuclei of radioactive high molecular weight nuclear proteins distinguished their patterns and those generated from the cytosol. These properties are consonant with a role for this process in the expression of androgen-induced changes in the rat ventral prostate. They are also consistent with the formation in situ of some nuclear proteins by a process that is partially androgen-dependent.