Nuclear non-histone proteins from rat ventral prostate cell under going hypertrophy of hyperplasia.

The distribution of nuclear non-histone proteins and their labelling with [¹⁴C]amino acids or [³²P]O₄ in rat ventral prostate cells undergoing hypertrophy (cell growth) or hyperplasia (cell division) were compared by SDS polyacrylamide gel electrophoresis. Marked quantitative changes in these proteins accompanied castration and replacement of hormone, but no absolute qualitative differences in their staining patterns were established. Preparations from cells undergoing hyperplasia were augmented in high molecular weight proteins and contained fewer proteins of <20000 D. The increased amounts of nuclear non-histone proteins from hormone-treated castrated rats were highly labelled by [¹⁴C]amino acids, but the molecular weights of radioactive proteins from cells undergoing hypertrophy were less diverse than those from replicating cells, Phosphorylation of nuclear non-histone proteins from short-term and long-term castrates, treated with testosterone propionate, was 170 and 60% greater than their controls. Proteins from 20–45 × 10³ D were actively phosphorylated. Nuclear extracts from dividing cells contained additional radioactive high molecular weight proteins and fewer phosphorylated lower molecular weight components. The distribution of phosphorylated proteins and newly synthesized proteins was dissimilar. Quantitative and possible qualitative differences in staining of nuclear proteins isolated in N-ethylmalleamideurea-phosphate buffer from normal or hormone-treated castrated rats were accentuated when they were separated by charge at pH 2.8. In replicating cells, a more generalized synthesis of acidic nuclear proteins from all molecular weight classes occurred, which were not as highly phosphorylated as less heterogeneous nuclear proteins from cells undergoing hypertrophy. Examination of the immediate and the subsequent events following androgen-induced cellular hypertrophy or hyperplasia in the ventral prostate permits their comparison in the same tissue.