scholarly journals The androgenic regulation of the activities of enzymes engaged in the synthesis of deoxyribonucleic acid in rat ventral prostate gland

1975 ◽  
Vol 152 (1) ◽  
pp. 1-16 ◽  
Author(s):  
P S Rennie ◽  
E K Symes ◽  
W J Mainwaring
Keyword(s):  
Dna Replication ◽  
Dna Polymerase ◽  
Hormonal Regulation ◽  
Prostate Gland ◽  
Experimental System ◽  
Physicochemical Characteristics ◽  
Ventral Prostate ◽  
Receptor System ◽  
Rat Ventral Prostate ◽  
Androgenic Regulation

1. The restoration of mitosis and growth of the prostate gland of castrated animals by androgens provides a favourable experimental system for studying the hormonal regulation of enzymes engaged in DNA replication. 2. Many DNA polymerase activities were identified in the prostate gland, but only a 9S form with a particular preference for denatured DNA as template was conspicuously enhanced by androgenic stimulation. 3. Thymidine kinase also provided a sensitive indicator of the hormonal regulation of DNA replication, and on electrophoretic criteria, one discrete form of the enzyme appeared precisely with the onset of mitoris. 4. Evidence is presented to support the view that DNA ligase activity is intimately associated in the process of DNA replication in the prostate gland. 5. A spectrum of deoxyribonuclease activities is present in the prostate gland, but only one form (pI7.0) can safely be said to be implicated in the process of DNA replication. 6. Androgenic stimulation of the prostate gland leads to the appearance of a component capable of denaturing or unwinding prostate DNA. This component is seemingly distinct from RNA or DNA polymerase activities on the basis of several distince physicochemical characteristics. 7. The conspicuous feature of all the changes in enzyme activities evoked by androgens in the prostate gland is their acute tissue- and steroid-specificity. Such changes could not be mimicked in liver or spleen and the regulatory role of androgens could not be simulated by other classes of steroid hormones. Particularly on the basis of studies with the anti-androgen cyproterone acetate, it is concluded that the changes are initially mediated by the androgen-receptor system and the high-affinity binding of 5α-dihydrotestosterone in the prostate gland. 8. The results are discussed in the context of the mechanism of action of androgens.

scholarly journals Initiation and elongation of polyribonucleotide chains on rat ventral-prostate chromatin transcribed by homologous ribonucleic acid polymerase B.

1977 ◽  
Vol 166 (2) ◽  
pp. 189-198 ◽  
Author(s):  
P Thomas ◽  
P Davies ◽  
K Griffiths
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
Prostate Gland ◽  
Ventral Prostate ◽  
Control Of Gene Expression ◽  
Rat Ventral Prostate ◽  
Associated Proteins ◽  
Ribonucleoside Triphosphate ◽  
Androgenic Steroids ◽  
Transcriptional Process

The characteristics of initiation of RNA synthesis and the elongation of RNA chains on rat ventral-prostate chromatin by RNA polymerase B were investigated by two methods. 1. Initiation was carried out under low-salt conditions with three ribonucleoside triphosphates, and elongation was begun in the absence of reinitiation by the addition of the fourth ribonucleoside triphosphate and increasing the salt concentration. 2. Stable initiation complexes were formed by preincubation of enzyme with template at 37 degrees C, elongation was started by the addition of all four ribonucleoside triphosphates and reinitiation or spurious RNA synthesis was prevented by rifamycin AF/013. The latter method gave more reliable results. The dependence of those parameters on the androgenic status of the animal was studied. During the first 24h after castration, elongation was mainly affected, whereas after 72h a smaller number of initiation sites for RNA polymerase B on chromatin was evident. Considerable diurnal variations in the various parameters were observed. Changes in the relative concentrations of the chromatin-associated proteins were also observed after castration. In the rat ventral-prostate gland androgenic steroids may not only influence one stage of the transcriptional process, but may affect many factors involved in the control of gene expression.

Biomarker analysis demonstrates a hypoxic environment in the castrated rat ventral prostate gland

2001 ◽  
Vol 81 (3) ◽  
pp. 437-444 ◽  
Author(s):  
Ahmad Shabsigh ◽  
Mohamed A. Ghafar ◽  
Alexandre de la Taille ◽  
Martin Burchardt ◽  
Steven A. Kaplan ◽  
...  
Keyword(s):  
Prostate Gland ◽  
Ventral Prostate ◽  
Rat Ventral Prostate ◽  
Hypoxic Environment ◽  
Biomarker Analysis

scholarly journals The androgenic regulation of superhelical-DNA nicking-closing enzyme in rat ventral prostate

1981 ◽  
Vol 196 (1) ◽  
pp. 195-202 ◽  
Author(s):  
J D Filipenko ◽  
P S Rennie ◽  
N Bruchovsky
Keyword(s):  
Enzyme Activity ◽  
Dna Synthesis ◽  
Chromatin Structure ◽  
Structural Organization ◽  
Time Course ◽  
Ventral Prostate ◽  
Rat Ventral Prostate ◽  
Dna Nicking ◽  
Androgenic Regulation

The activity of superhelical-DNA nicking-closing enzyme (NC enzyme) was measured in nuclei from rat ventral prostate by a fluorimetric assay based on the binding of ethidium bromide to supercoiled phage-PM2 DNA. The nuclear concentration of NC-enzyme activity declined rapidly after castration, although this response could be prevented by daily administration of dihydrotestosterone. The low NC-enzyme activity in involuted prostates (10% of normal) was restored to normal after 8-10 days of treatment with androgen. In the regenerating prostate the time course of restoration of NC-enzyme activity was not in phase with that of DNA synthesis. Examination of nucleosome repeat lengths and the arrangement of nucleosomes along the chromatin fibre revealed no differences in the structural organization of chromatin in prostates with high or low NC-enzyme activity. Together, these results suggest that the major role of NC enzyme is related to the onset and maintenance of differentiation in the prostate and that the activity of this enzyme is not expressed through gross alterations in chromatin structure.

scholarly journals Cascade Induction of c-fos, c-myc, and Heat Shock 70K Transcripts during Regression of the Rat Ventral Prostate Gland

1988 ◽  
Vol 2 (7) ◽  
pp. 650-657 ◽  
Author(s):  
Ralph Buttyan ◽  
Zahra Zakeri ◽  
Richard Lockshin ◽  
Debra Wolgemuth
Keyword(s):  
Heat Shock ◽  
Prostate Gland ◽  
Ventral Prostate ◽  
Rat Ventral Prostate

MEASUREMENT OF FREE AND OCCUPIED CYTOPLASMIC AND NUCLEAR ANDROGEN RECEPTOR SITES IN RAT VENTRAL PROSTATE GLAND

1977 ◽  
Vol 74 (3) ◽  
pp. 393-404 ◽  
Author(s):  
PETER DAVIES ◽  
PHILIP THOMAS ◽  
KEITH GRIFFITHS
Keyword(s):  
Androgen Receptor ◽  
Specific Binding ◽  
Prostate Gland ◽  
Ventral Prostate ◽  
Reliable Estimate ◽  
Exchange Method ◽  
Receptor Proteins ◽  
Receptor Sites ◽  
Rat Ventral Prostate ◽  
Fold Excess

SUMMARY A method has been developed which allows the estimation of occupied and unoccupied androgen receptor sites in both cytoplasmic and nuclear fractions of rat ventral prostate. The procedure involves precipitation of receptor proteins and incubation of precipitates with labelled 5α-dihydrotestosterone. Uptake of 3H-labelled steroid at 0–4 °C gives an indication of free receptor, whereas binding at a raised temperature (15 °C) allows estimation of occupied receptor. Non-specific binding was measured in the presence of a 100-fold excess of unlabelled 5α-dihydrotestosterone. The exchange method was specific for androgens, and specific binding was detected only in fractions of androgen-dependent tissues. The method can be applied to cytosol, whole nuclei, chromatin and salt-extractable and salt-resistant protein preparations from nuclear fractions, and gives a reliable estimate of total receptor sites when occupied as compared with control measurements of unoccupied sites.

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