THE BINDING OF [1,2-3H]TESTOSTERONE WITHIN NUCLEI OF THE RAT PROSTATE

1969 ◽  
Vol 44 (3) ◽  
pp. 323-333 ◽  
Author(s):  
W. I. P. MAINWARING
Keyword(s):  
Molecular Weight ◽  
Equilibrium Dialysis ◽  
Prostate Gland ◽  
Ventral Prostate ◽  
Rat Tissues ◽  
Receptor Complex ◽  
Rat Prostate ◽  
Binding Component

SUMMARY The specificity of the binding of [1,2-3H]testosterone to nuclei of various rat tissues in vivo has been studied. A significant amount of radioactivity was retained in the nuclei of androgen-dependent tissues only, particularly the ventral prostate gland. The bound radioactivity was only partially recovered as [1,2-3H]testosterone; the remainder was identified as [3H]5α-dihydrotestosterone. Efforts were made to characterize the binding component, or 'receptor', in prostatic nuclei. On digestion of nuclei labelled in vivo with [1,2-3H]testosterone, with enzymes of narrow substrate specificity, only trypsin released tritium, suggesting that the receptor is a protein. On the basis of subfractionation studies of labelled nuclei, the receptor is an acidic protein. The androgen—receptor complex could be effectively extracted from the prostatic nuclei in 1 m-NaCl and from the results of fractionations on a calibrated agarose column, the complex has a molecular weight 100,000–120,000. The specificity of the binding of steroids to such 1 m-NaCl extracts in vitro was investigated by the equilibrium dialysis procedure. Under these conditions, the specificity of the binding of [1,2-3H]testosterone demonstrated in vivo could not be simulated. The receptor is probably part of the chromatin complex but its precise intranuclear localization cannot be determined by biochemical procedures alone.

scholarly journals Studies on the form and synthesis of messenger ribonucleic acid in the rat ventral prostate gland, including its tissue-specific stimulation by androgens

1974 ◽  
Vol 137 (3) ◽  
pp. 513-524 ◽  
Author(s):  
W. Ian P. Mainwaring ◽  
Peter A. Wilce ◽  
Allan E. Smith
Keyword(s):  
Prostate Gland ◽  
Sodium Dodecyl ◽  
Ventral Prostate ◽  
Experimental Conditions ◽  
Free System ◽  
Cell Free System ◽  
Messenger Ribonucleic Acid ◽  
Selective Incorporation

1. When prostate polyribosomes are labelled with radioactive precursors in vivo and subsequently dissociated with sodium dodecyl sulphate, a heterogeneous 6–15S RNA species may be identified that possesses all of the distinctive properties of mRNA. 2. Apart from the selective incorporation of 5′-fluoro-orotic acid into this 6–15S RNA component, it is bound by nitrocellulose filters under experimental conditions where only poly(A)-rich species of RNA are specifically retained. Most importantly, however, only the 6–15S RNA fraction is capable of promoting the incorporation of amino acids into peptide linkage in an mRNA-depleted cell-free system derived from ascites-tumour cells. 3. With the development of a simpler method for labelling the total RNA fraction of the prostate gland in vitro, the poly(A)-enriched RNA fraction may be readily isolated by adsorption and elution from oligo(dT)-cellulose. The synthesis of the poly(A)-enriched 6–15S RNA fraction is stringently controlled by androgens in a highly tissue- and steroid-specific manner. 4. From an analysis of the proteins synthesized in the ascites cell-free system in the presence of the poly(A)-rich RNA fraction, it appears that protein synthesis in the prostate gland is stimulated in a rather general way, even during the earliest phases of the androgenic response. This conclusion may require modification when more specific means of analysis are available than those used in the present investigation. 5. The implications of these findings to the mechanism of action of androgens are discussed.

STUDIES ON THE CONVERSION OF OESTRADIOL LINKED TO A CYTOSTATIC AGENT (ESTRACYT®) IN VARIOUS RAT TISSUES

1976 ◽  
Vol 82 (3) ◽  
pp. 661-672 ◽  
Author(s):  
Per Aage Høisaeter
Keyword(s):  
Prostatic Cancer ◽  
Nitrogen Mustard ◽  
Phosphate Group ◽  
Ventral Prostate ◽  
Rat Tissues ◽  
Cytostatic Agent ◽  
Metabolic Conversion ◽  
Different Tissues

ABSTRACT Estracyt®, a compound of nitrogen-mustard linked to oestradiol phosphate, is used in the treatment of human prostatic cancer. The metabolism of this compound has been studied in different tissues of the rat both in vivo and in vitro. The phosphate group in position 17 of the oestradiol moiety is rapidly split off from the compound. An oestrone-cytostatic compound was extractable from the liver half an hour after the injection of Estracyt®. In addition the in vitro results showed that only the liver was able to convert the oestradiol-cytostatic compound to an oestrone-cytostatic one. When animals were killed 24 h after a 3-day period of Estracyt® treatment, the dominating metabolite in the ventral prostate was an oestrone-cytostatic compound, but traces of free oestrone could also be demonstrated. No such compound, however, was found in liver, diaphragm or blood at this time. It is concluded that in vivo an oestrone-cytostatic compound seems to be preferentially retained in the ventral prostate after Estracyt® injection whilst the metabolic conversion of the oestradiol-cytostatic compound into an oestrone-cytostatic one possibly occurs in the liver.

scholarly journals Specific changes in the messenger ribonucleic acid content of the rat ventral prostate gland after androgenic stimulation. Evidence from the synthesis of aldolase messenger ribonucleic acid

1974 ◽  
Vol 144 (2) ◽  
pp. 413-426 ◽  
Author(s):  
W I P Mainwaring ◽  
F R Mangan ◽  
R A Irving ◽  
D A Jones
Keyword(s):  
Ribonucleic Acid ◽  
De Novo ◽  
Prostate Gland ◽  
Ventral Prostate ◽  
Mrna Synthesis ◽  
Hormonal Stimulation ◽  
Messenger Ribonucleic Acid ◽  
Stimulation Of

1. Aldolase was selected as a suitable marker for following the androgenic regulation of mRNA synthesis in the prostate gland. 2. Antibodies raised in rabbits against crystalline prostate aldolase were used to monitor the synthesis of this androgen-induced enzyme after hormonal stimulation of castrated animals, by using procedures in vivo and in vitro for the translation of prostate poly(A)-rich mRNA. 3. After androgenic stimulation in vivo the poly(A)-rich mRNA was isolated from the prostate gland and other tissues of castrated rats, and added to a protein-synthesizing system in vitro derived from Krebs II ascites-tumour cells. By using this approach it was found that androgens regulate the synthesis of aldolase mRNA in a highly tissue-specific manner. Stimulation of aldolase mRNA synthesis reached a maximum after 8h of androgenic treatment and then declined. 4. The androgenic control of aldolase mRNA synthesis was also investigated in vivo. After treatment of castrated animals with various steroids in vivo [35S]methionine was injected directly into the prostate gland, and labelled aldolase was selectively precipitated from isolated polyribosomes with anti-aldolase serum. The regulation of aldolase mRNA synthesis in the prostate gland was stringently steroid-specific and could only be evoked by androgens. After a single injection of testosterone, aldolase synthesis reached a maximum after 16h of hormonal stimulation and then declined. 5. Although androgens exert significant control over transcriptional processes in the prostate gland, and appear to regulate the synthesis of aldolase mRNA de novo, the possibility exists for additional means of control at the translational level of aldolase synthesis. The results are discussed in the context of the overall mechanism of action of androgens.

BIOLOGIC AND BIOCHEMICAL EFFECTS OF ANTI-ANDROGENS ON RAT VENTRAL PROSTATE

1974 ◽  
Vol 75 (2) ◽  
pp. 385-397 ◽  
Author(s):  
Jack Geller ◽  
Kevin McCoy
Keyword(s):  
Complex Formation ◽  
Protein Complex ◽  
Ventral Prostate ◽  
Common Denominator ◽  
Biochemical Effects ◽  
Protein Complex Formation ◽  
Biologic Effects ◽  
Rat Prostate

ABSTRACT To determine whether the similarity of biologic effects of two antiandrogens, cyproterone acetate (Cyp A) and edogesterone (PH-218), could be related to one or more common biochemical effects, we have compared the effects of both drugs on 3H testosterone (3HT) entry into cells, binding to specific cytosol and nuclear androphiles, and conversion to dihydrotestosterone (DHT). In chronic in vivo studies, both Cyp A and PH-218 reduced rat prostate weights by approximately 50% and specific cytosol steroid-protein complex formation by approximately 60 %. At the same time, Cyp A decreased the formation of nuclear steroid-protein complex to 10% of control values, compared with 40% for PH-218. In addition, Cyp A, but not PH-218, significantly decreased total 3HT uptake by the prostate. Similar effects of Cyp A on 3HT uptake, binding, and metabolism were noted in acute in vivo and in vitro experiments. PH-218 effects on these same parameters were reduced in acute, compared to chronic, studies. Neither drug significantly affected the conversion of T to DHT. Despite quantitative differences between Cyp A and PH-218, these studies support the concept that the biochemical common denominator for the biologic effects of anti-androgens is inhibition of specific steroid-protein complex formation in both cytosol and nucleus.

scholarly journals Studies on the solubilized ribonucleic acid polymerase from rat ventral prostate gland

1971 ◽  
Vol 123 (4) ◽  
pp. 619-628 ◽  
Author(s):  
W. I. P. Mainwaring ◽  
F. R. Mangan ◽  
B. M. Peterken
Keyword(s):  
Time Course ◽  
Prostate Gland ◽  
Exchange Chromatography ◽  
Ventral Prostate ◽  
Enzyme Preparations ◽  
Rat Ventral Prostate ◽  
Rapid Stimulation ◽  
Androgenic Steroids

1. By using ultrasonic treatment in media of high ionic strength, the RNA polymerase activities associated with prostatic nuclei and nucleoli can be completely solubilized. Such enzyme preparations are entirely dependent on the provision of added DNA for full activity. 2. The solubilized enzymes from the nucleolar and extranucleolar regions can be separated by ion-exchange chromatography. 3. Based on differences in the optimum DNA templates, pH optima and the effects of ammonium sulphate on the activities in vitro, Mn2+- and Mg2+-specific enzymes are associated with both the nucleolar and extranucleolar regions of prostatic nuclei. 4. Androgenic hormones administered in vivo have a particularly pronounced effect on the activity of Mg2+-dependent enzyme associated with the isolated prostatic nucleolus. 5. Time-course experiments in vivo show that androgens induce a rapid stimulation of the solubilized Mg2+-dependent nucleolar enzyme before a pronounced activation of nucleolar chromatin can be measured. 6. The implications of these findings to the mechanism of action of androgenic steroids are discussed.

scholarly journals The control of the form and function of the ribosomes in androgen-dependent tissues by testosterone

1973 ◽  
Vol 134 (3) ◽  
pp. 795-805 ◽  
Author(s):  
W. I. P. Mainwaring ◽  
P. A. Wilce
Keyword(s):  
Protein Synthesis ◽  
Prostate Gland ◽  
Concomitant Administration ◽  
Ventral Prostate ◽  
Hormonal Stimulation ◽  
Pronounced Increase ◽  
Form And Function ◽  
Mandatory Requirement

1. The ribosome content of the rat ventral prostate gland is controlled by the concentrations of circulating androgens and the polyribosomal complement of the total population of ribosomes is acutely dependent on androgenic stimulation. After the administration of testosterone to castrated rats in vivo, there is a pronounced increase in the amounts of heavy (150–240S) polyribosomes. 2. These results are consistent with a pronounced increase in the mRNA and rRNA content of the prostate gland after the administration of testosterone in vivo. 3. From studies conducted both in vitro, the heavy prostate polyribosomes formed after androgenic stimulation are particularly active in protein synthesis. 4. The androgen-stimulated increase in the formation of prostate polyribosomes has a mandatory requirement for sustained RNA and protein synthesis. 5. Since the androgen-mediated increase in prostate polyribosomes may also be suppressed by the concomitant administration of certain anti-androgenic steroids in vivo, the response in polyribosome formation is probably initiated by the binding of a metabolite of testosterone, 5α-dihydrotestosterone, in the prostate gland. 6. The relevance of these findings to the pronounced increase in protein synthesis in androgen-dependent tissues after hormonal stimulation is discussed.

ANDROGEN DEPENDENCE OF RAT PROSTATIC 3α-HYDROXYSTEROID DEHYDROGENASE

1978 ◽  
Vol 79 (1) ◽  
pp. 143-144 ◽  
Author(s):  
R. MASSA ◽  
M. MAS GARCIA ◽  
L. MARTINI
Keyword(s):  
Anterior Pituitary ◽  
Reductase Activity ◽  
Prostate Gland ◽  
Hydroxysteroid Dehydrogenase ◽  
Irreversible Reaction ◽  
Dehydrogenase System ◽  
Rat Prostate ◽  
Biological Actions

Department of Endocrinology, University of Milan, Via A. del Sarto 21, 20129 Milan, Italy (Received 8 May 1978) It is well established that the rat prostate gland converts testosterone mainly into 5α-androstan-17β-ol-3-one (5α-dihydrotestosterone, 5α-DHT) and to a lesser extent into 5α-androstan-3α,17β-diol (5α-tetrahydrotestosterone, 5α-THT). This occurs, both in vivo and in vitro, through the action of a 5α-reductase and a 3α-hydroxysteroid dehydrogenase system (Baulieu, Lasnitzki & Robel, 1968; Bruchovsky & Wilson, 1968; Gloyna & Wilson, 1969; Kniewald, Massa & Martini, 1971). It has also been recognized that, although the 5α-reduction of testosterone is an irreversible reaction, the reduction of 5α-DHT to 5α-THT is reversible (Becker, Grabosch, Hoffmann & Voigt, 1973; Cresti & Massa, 1977). Consequently, the question has been raised as to whether the biological actions of 5α-THT are attributable to the compound as such or to 5α-DHT. At the anterior pituitary level, 5α-reductase activity is increased by castration and decreased

scholarly journals Testosterone action in the rat ventral prostate. The effects of diethylstilboestrol and cyproterone acetate on the metabolism of [3H]testosterone and the retention of labelled metabolites by rat ventral prostate in vivo and in vitro

1971 ◽  
Vol 125 (1) ◽  
pp. 81-91 ◽  
Author(s):  
J. E. Belham ◽  
G. E. Neal
Keyword(s):  
Cyproterone Acetate ◽  
Prostatic Carcinoma ◽  
Prostate Gland ◽  
Target Organ ◽  
Ventral Prostate ◽  
Nuclear Retention ◽  
Rat Ventral Prostate ◽  
Androgenic Effect

Recent reports have indicated that the prior metabolism of testosterone by the secondary sexual tissues may be necessary for its androgenic effect. The effects of two anti-androgens, diethylstilboestrol and cyproterone acetate (17α-acetoxy-6-chloro-1,2α-methylenepregna-4,6-diene-3,20-dione) used in the chemotherapy of human prostatic carcinoma, have been examined on both the metabolism of testosterone and the retention of its metabolites by the rat ventral prostate gland. Cyproterone acetate was found to inhibit the retention of labelled metabolites of [3H]-testosterone by prostatic nuclei, both in vivo and in vitro. This inhibition appeared to be competitive. In contrast with its effect on nuclear retention of metabolites of testosterone, cyproterone acetate had no significant effect on the metabolism of [3H]testosterone by rat ventral prostate tissue. Diethylstilboestrol similarly had little effect on the metabolism of [3H]testosterone by prostatic tissue, although it did appear partially to inhibit its initial metabolism in all the incubation systems used. Diethylstilboestrol inhibited the nuclear retention of dihydrotestosterone when both [3H]testosterone and diethylstilboestrol were injected intraperitoneally in vivo, but had no effect on dihydrotestosterone retention when both testosterone and diethylstilboestrol were supplied directly to the prostate either in vivo or in vitro. It was concluded that if diethylstilboestrol has an anti-androgenic effect at the level of the target organ as distinct from its effect on androgen production by the testes, then it is probably due to a mechanism differing from that of cyproterone acetate.

scholarly journals A reconstituted cell-free system for the specific transfer of steroid–receptor complexes into nuclear chromatin isolated from rat ventral prostate gland

1971 ◽  
Vol 125 (1) ◽  
pp. 285-295 ◽  
Author(s):  
W. I. P. Mainwaring ◽  
Brenda M. Peterken
Keyword(s):  
Prostate Gland ◽  
Ventral Prostate ◽  
Free System ◽  
Tissue Specific ◽  
Receptor Complexes ◽  
Rat Ventral Prostate ◽  
Reconstituted System ◽  
Androgenic Steroids

1. A system has been developed for the specific transfer of [3H]dihydrotestosterone–receptor complexes into prostatic chromatin in vitro. 2. Under optimum conditions the overall transfer of [3H]dihydrotestosterone into purified chromatin in this reconstituted system is entirely consistent with the results obtained in whole tissue both in vivo and in vitro. 3. The transfer of [3H]dihydrotestosterone into chromatin is tissue-specific and maximal into chromatin isolated from androgen-dependent tissues. 4. The tissue specificity is maintained at two levels: first, in the presence of specific cytoplasmic androgen-receptor proteins; secondly, by the nature and composition of the chromatin itself. 5. Evidence is presented that androgenic steroids in vivo may maintain the tissue-specific nature of chromatin in androgen-dependent tissues by the selective induction of nuclear protein synthesis. 6. The relevance of these findings to the mechanism of action of androgenic steroids is discussed.

INHIBITION OF STEROID 5α-REDUCTASE IN VIVO: EFFECT ON SUPPRESSION OF LUTEINIZING HORMONE AND STIMULATION OF ACCESSORY SEX ORGANS BY TESTOSTERONE IN THE ORCHIDECTOMIZED RAT

1979 ◽  
Vol 81 (2) ◽  
pp. 209-220 ◽  
Author(s):  
LIDIA WEI LIU KAO ◽  
JUDITH WEISZ
Keyword(s):  
Prostate Gland ◽  
Male Rats ◽  
Ventral Prostate ◽  
Promoting Effect ◽  
Accessory Sex Organs ◽  
Pituitary Glands ◽  
Lh Secretion ◽  
Carboxylic Acid Derivative

An inhibitor of 5α-reductase, the 17β-carboxylic acid derivative of testosterone (testosterone-17βCA), has been used to evaluate the importance of the 5α-reduction of testosterone in its action on the suppression of LH secretion in male rats. The potential of testosterone-17βCA to inhibit the formation of 5α-dihydrotestosterone (DHT) was first demonstrated in vitro. When homogenates of hypothalami or anterior pituitary glands were incubated with [3H]testosterone in the presence of a 50-fold excess of testosterone-17βCA, the formation of labelled DHT was inhibited by more than 80%. Adult male rats that had been castrated for 1–2 months were fitted with chronic intravenous catheters and implanted with silicone elastomer sheets: one group received one sheet, 0·5–2·0 cm2 in size containing 1·6% testosterone, a second group received one 50 cm2 sheet containing 1·6% testosterone-17βCA and a third group received two sheets, one sheet 50 cm2 in size containing 1·6% testosterone-17βCA and the second ranging in size from 0·5 to 2·0 cm2 and containing 1·6% testosterone. Blood was withdrawn daily from each rat over a 4–5 day period after implantation of the steroids and the level of LH in the plasma was measured by radioimmunoassay. The seminal vesicles and the ventral prostate gland were removed at autopsy on day 4 or 5; the weights of these organs were shown to have increased progressively as the size of the implant of testosterone increased. In contrast, the level of LH in the plasma was suppressed to a comparable extent by implants of testosterone between 0·6 and 2 cm2, whereas a 0·5 cm2 implant of testosterone had no effect. Implants of testosterone-17βCA alone did not influence the weight of the accessory organs or the level of LH. When testosterone-17βCA and testosterone were implanted together, the growth-promoting effect of the latter on the accessory sex organs was significantly reduced. The effectiveness of testosterone in suppressing the level of LH in the plasma of these animals was not influenced by the presence of testosterone-17βCA and in certain instances the level was raised.

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