Two-dimensional electrophoresis of proteins from different lobes of the rat prostate and seminal vesicle

Two-dimensional ISO-DALT electrophoresis of cytosols and secretions from various lobes of the rat prostate gland and seminal vesicle reveals major differences in intracellular and secretory protein patterns. This study confirms a previous study utilizing one-dimensional electrophoresis. The dorsal lobe and coagulating gland appear to secrete predominantly relatively basic proteins (molecular mass, MM, 70,000–200,000 daltons, pI > 7) in contrast to the ventral lobe, which secretes proteins of a more acidic character (pI 4–5). The majority of proteins in the latter case appear to represent subunits of the major secretory protein of the rat ventral prostate, prostatein. At least one secretory protein is relatively specific for the lateral lobe (MM 16,000 daltons, pI 4.5). The vesicular secretion also contains relatively greater quantities of basic proteins than acidic but with varying molecular mass (12,000–100,000 daltons). This study extends the search for specific protein markers for different lobes of the rat accessory sex glands and provides additional biochemical data which can be exploited in the future to isolate selected secretory proteins on a large scale for antibody production.     

Androgen regulation of spermidine synthase expression in the rat prostate

BACKGROUND: Spermidine synthase, an essential enzyme in the polyamine synthesis pathway, was identified as one of the androgen-response genes in the rat ventral prostate. Characterization of androgen regulation of spermidine synthase is important to the understanding of androgenic regulation of polyamine synthesis. METHODS: Full-length cDNA encoding rat spermidine synthase was isolated from a lambdaZAP cDNA phage library. Young male adult Sprague-Dawley rats were used for castration and androgen replacement. Northern blot and in situ hybridization were used to characterize gene expression. RESULTS: The amino acid sequence of rat spermidine synthase shares 99% and 94% identity with that of mouse and human spermidine synthase, respectively. Spermidine synthase gene is abundantly expressed and regulated by androgens in the ventral, dorsal, and lateral lobes of the rat prostate, and its expression is localized to the epithelial cells. Spermidine synthase also is regulated by androgens in the seminal vesicles but not in the muscle, brain, kidney, thymus, heart, or liver, suggesting that this enzyme is responsive to androgen in the male sex accessory organs only. The expression of spermidine synthase and two other enzymes involved in polyamine synthesis, S-adenosylmethionine decarboxylase and ornithine decarboxylase, are regulated by androgens coordinately. CONCLUSIONS: Spermidine synthase is most abundantly expressed and regulated by androgens in the prostatic epithelial cells, suggesting that regulation of spermidine synthase is likely a key step in coordinated androgen regulation of polyamine synthesis in the prostate.     

Ultrasound-guided seminal vesicle biopsies in prostate cancer

Invasion of prostatic adenocarcinoma into the seminal vesicles (SV) is generally accepted as an index of poor prognosis. The pre-operative identification of SV invasion is an important element in staging since it may alter subsequent treatment decisions. We studied the possibility of diagnosing SV invasion with two biopsies from the junction between the prostate and seminal vesicles. Also we studied the correlation of several prognostic factors with the risk of clinical stage T(1,2,3) prostate cancer patients of having cancer growth into the seminal vesicles. Consecutive patients referred for transrectal ultrasound (TRUS) and biopsy because of clinical suspicion of prostate cancer were examined. This staging procedure was evaluated in patients who underwent a pelvic lymphadenectomy and radical retropubic prostatectomy (RRP). In 83 out of 138 patients prostate cancer was detected whereas 55 patients had benign disease. In 44% of prostate cancer patients a positive SV biopsy was found. The accuracy of the biopsies adjacent to the junction of the SV and the prostate was 91%. The best predictors for SV invasion were tumor grade of the biopsy sample (P<0.001), serum prostate-specific antigen (PSA) (P<0.0005), PSA density (P<0.0005) and clinical stage (P<0.0005). No significance was found in the relation to seminal vesicle involvement with free/total (f/t) PSA ratio (P=0.588) for the prostate cancer group (SV+ and SV-). In a receiver operating characteristic curves analysis, PSA density was significantly more accurate for prediction of SV invasion than PSA or f/t PSA ratio. In five prostatectomized patients (and negative SV biopsy) no SV invasion was found in the final pathologic examination either. SV biopsy at the junction of the SV and prostate is accurate for staging with high efficacy and low morbidity. To predict SV invasion in prostate cancer patients, PSA density was more accurate than PSA or f/t PSA ratio. The determination of the f/t PSA ratio in patients with low and intermediate PSA levels (eg <15 &mgr;g/L) is not useful to estimation of the risk of seminal vesicle involvement. The combination of serum PSA concentration, PSA density, tumor grade from the biopsy specimens ad clinical stage provides the best prediction of SV invasion. These parameters are identical to the conventional predictors of pathology after RRP. SV biopsies may provide additional information; if one or both basal biopsies are positive, a clinical T(1,2) disease is altered to T(3). Hence SV biopsy is useful for selection of patients who might obtain good results from RRP for prostate cancer. Prostate Cancer and Prostatic Diseases (2000) 3, 100-106     

Peptidergic innervation within the prostate gland and seminal vesicle

Summary An immunohistochemical study in which antisera against several neuropeptides were used demonstrated the presence of neuropeptide Y(NPY) and vasoactive intestinal polypeptide (VIP) immunoreactivity in nerve fibers in the human prostate gland and seminal vesicle, whereas no immunostaining for substance P and calcitonin gene-related peptide was observed. The peptidergic innervation was found to be generally moderate to low. NPY-and VIP-immunoreactive fibers were localized in the subepithelial connective tissue as well as the smooth muscle layers in both organs, although the peptidergic fiber networks were more prominent in the seminal vesicle. Most NPY-immunoreactive fibers were observed in the musculature of the seminal vesicle.In addition, NPY-and VIP-immunoreactive fibers were demonstrated in the walls of blood vessels. The results of our study suggest that the innervation of the prostate gland and seminal vesicle by various neuroactive peptides may be involved in the autonomic regulation of these organs in adult man, as well as sympathetic and parasympathetic nerve fibers.The work reported in this paper was supported by the Walter-Schulz-Stiftung and the Friedrich-Baur-Stiftung     

A novel method of seminal vesicle preparation in isolated seminal vesicle experiments in the rat: ring preparation

In this study, we evaluated the efficacy of a novel method of seminal vesicle (SV) preparation-ring preparation method-in isolated SV experiments in the rat. Rat SVs were prepared as strips and rings and applied to organ baths. The relaxation responses by sodium nitroprusside or doxazosin and contractile responses by electrical field stimulation (EFS) were recorded in both groups. We compared the proportion of tissues that showed consistent responses to the stimuli-drug or EFS-in both groups. And magnitudes of the contractile or relaxation responses were also evaluated in the two groups. In strip preparations (n=20), six tissues (30%) showed stable responses to drugs and were regarded to be useful. However, in ring preparations (n=20), 13 tissues (65%) showed stable responses (P<0.001). Similarly, consistent contractile responses to the EFS were recorded in eight strips (40%) and 13 rings (65%) (n=20 in each group; P<0.05). The magnitudes of the relaxations by drugs were not different between the two methods (P=0.42) and the contractions by EFS were higher in ring preparations (P<0.05). The ring preparation seems to be better for responses to drugs and EFS compared with the strip preparations and, therefore, might be an alternative technique for in vitro SV experiments.     

Sex steroid-induced changes in collagen of the prostate and seminal vesicle of rats

The effects of androgen alone or in combination with estrogen or prolactin on the collagen of the prostate and seminal vesicles were studied in prepubertal and adult rats. Castration decreased the collagen content of the male accessory sex organs of both prepubertal and adult rats. Androgens showed stimulatory effects in castrated rats irrespective of the age. However, in intact animals, the stimulatory effects of androgens were evident only before puberty. Only the seminal vesicle of prepubertal rats responded to the stimulatory effect of estrogen given along with androgens. Prolactin did not elicit any appreciable effect either in the prostate or the seminal vesicles when administered along with androgens.     

Light microscopic morphometric analysis of castration effects in the different lobes of the rat prostate

The morphologic effects of androgen deprivation in the different lobes of the rat prostate were examined by light microscopic morphometry. The prostates of Wistar male rats (260-340 g) were fixed in situ by glutaraldehyde perfusion in castrated animals 1 week after gonadectomy and in intact animals. The ventral (VP), dorsal (DP), and lateral (LP) lobes as well as the coagulating gland (CG) were dissected out, weighed, and processed for light microscopy. Using stereologic methods the following parameters were estimated for each lobe: volume fraction of connective tissue, epithelium and glandular lumina, average epithelial height, average epithelial cell volume, and total number of epithelial cells. Castration leads to a 58-76% reduction of the wet weight of all prostatic lobes. The decrease of glandular tissue is greater in VP than in LP, DP, and CG. In VP and LP, there is a 39-45% reduction of the epithelial height, and this effect is less pronounced in DP and CG. For all lobes, the shrinkage of average epithelial cell volume is in the same range (25-30%). Moreover, in VP and LP, there is a 70% reduction of the total number of cells, whereas the reduction is less in DP and CG. It thus seems that the reduction of prostatic epithelial tissue mass upon castration is due to a reduction of the number of cells as well as a reduction of the volume of individual cells. VP and LP appear to be more androgen-dependent than DP and CG.     

Androgen receptor levels and androgen contents in the prostate lobes of intact and testosterone-treated Noble rats

Plasma testosterone (T) levels were correlated with androgen receptors, tissue content of T, and 5 alpha-dihydrotestosterone (DHT) in the three anatomically-discrete prostate lobes of intact and castrated Noble (Nb) rats bearing T-filled silastic capsules. Differences in androgen receptor content and tissue androgen levels were observed among the three prostatic lobes of intact Nb rats. Total (cytosolic and nuclear) androgen receptor levels were highest in the ventral prostate followed by the dorsolateral and anterior prostate lobes. In the ventral and anterior prostate, androgen receptors were found to be equally distributed between cytosols and nuclear extracts, whereas in the dorsolateral prostate, androgen receptors were predominantly nuclear (cytosolic: nuclear = 1.5). The ventral prostate had the highest total androgen content and DHT was the major tissue androgen in all three lobes. The ratio of tissue DHT:T varied among the lobes; the highest value was observed in the dorsolateral prostate. The higher proportions of nuclear androgen receptor, as well as the elevated tissue DHT:T found in the dorsolateral prostate compared to other lobes, suggest that differences in the androgen activation process may exist between the dorsolateral prostate and other prostatic lobes. Despite lower plasma and tissue T levels, the DHT content, weight and cytodifferentiation in all lobes of T-treated castrated rats closely approximated the situation found in intact animals. Total androgen receptor levels were, however, elevated in all prostatic lobes of T-treated, castrated rats as compared to intact controls. These increases were primarily attributed to the augmented levels of androgen receptor in the nuclear extracts of the three prostate lobes. Exposure of the prostate to a constant level of T, produced by silastic implantation, might be responsible for the higher total androgen receptor levels and enhanced nuclear androgen receptor retention found in the prostates of T-treated, castrated rats.     

Reverse zymography studies of protease inhibitors in the secretions of different lobes of rat prostate

The purpose of this study was to determine whether protease inhibitors were a constituent of secretions from the different lobes of the rat prostate. A reverse zymography method was used employing gelatin substrate-SDS-polyacrylamide gel electrophoresis to detect inhibitors of trypsin in secretions of the ventral, lateral, and dorsal prostate lobes of the Sprague-Dawley rat. Inhibitors of approximately 34 and 63 kDa were detected in ventral prostate secretion and of about 63 and 73 kDa were found in lateral lobe secretion. However, no inhibitor activities were detected in secretions of the dorsal lobe. The protease inhibitors of ventral prostate secretion were partially purified by preparatory isolectric focusing and SDS-polyacrylamide gel electrophoresis. The 34-kDa (pI 5.6-6.4) inhibitor had a higher activity against trypsin, whereas the 63-kDa (pI 6.4-7.0) inhibitor was more active against chymotrypsin. The rat prostate appears to have a lobe-specific distribution of secretory serine protease inhibitors.     

Primary seminal vesicle carcinoma detected at transurethral resection of prostate

We present a case of primary seminal vesicle carcinoma detected at transurethral resection. The clinical presentation, radiologic findings, and pathologic features of these tumors are reviewed. Grossly, seminal vesicle carcinoma is poorly circumscribed and solid or solid/cystic and may be misinterpreted as an abscess or hemorrhage on radiologic examination. Although a definitive diagnosis often cannot be given until after complete resection, we describe the findings indicative of seminal vesicle origin, including papillary histologic architecture, sometimes with mucinous differentiation, and a characteristic immunophenotype positive for CA-125 and cytokeratin 7, but negative for prostate-specific antigen and cytokeratin 20.     

Prostatic binding protein,polyamine, and dna synthesis in rat ventral prostate cells

Prostatic binding protein (PBP), polyamine, and DNA synthesis were examined in primary cultures of rat ventral prostate cells. Soon after aggregates of prostate cells were placed in culture, PBP synthesis fell dramatically and DNA synthetic activity in the epithelial cells increased. The amount of polyamines that were labeled with [³H] from [³H]ornithine fell transiently, but rose again at or before the peak of DNA synthesis. Individual ³H-labeled polyamines in cells and medium were dansylated and separated by thin-layer chromatography. The ratio of [³H]Spermidine plus [³H]Spermine to [³H]Putrescine in the culture medium declined as DNA synthesis increased. Ornithine decarboxylase (ODC) activity fell dramatically along with PBP synthesis even as DNA synthesis and ³H-labeled polyamines increased in the prostate-cell cultures. These results support others that suggest that high ODC activity in prostate epithelial cells is a correlate of prostate epithelial cell function rather than proliferation. However, prostate epithelial cells retain the capacity to synthesize significant levels of polyamines from ornithine (especially Putrescine) during proliferation even when ODC activity is low.     

Hoxa-13 gene mutation results in abnormal seminal vesicle and prostate development

The role of Hoxa-13 in postnatal morphogenesis of the male accessory sex organs was assessed by correlating the Hoxa-13 expression domain with phenotypic abnormalities in heterozygous Hypodactyly mutants. Hypodactyly is a naturally occurring semi-dominant mutation that results from a 50-base pair deletion in exon one of the Hoxa-13 allele. We demonstrate that Hoxa-13 is broadly expressed in the developing lower genitourinary tract and that the Hypodactyly mutation results in a specific phenotype characterized by decreased size and branching of the dorsolateral and ventral prostate and abnormal seminal vesicle morphology. This phenotype partially overlaps the genitourinary phenotype observed in Hoxd-13 deficient mice and comparison showed similar domains of Hoxa-13 and Hoxd-13 expression in the lower genitourinary tract. The similarity in expression and overlap in phenotype resulting from mutation is consistent with additive function and partial functional redundancy of Hoxa-13 and Hoxd-13 in male accessory sex organ development.     

Testosterone replacement therapy and prostate/seminal vesicle volume in Klinefelter's syndrome

Volume of prostate and seminal vesicles was measured in patients with Klinefelter's syndrome by means of transrectal ultrasonography before and after testosterone replacement therapy. Continuous suppression of plasma gonadotropin levels was not observed, and plasma levels of testosterone did not maintain the normal range. However, volume of prostate (p less than 0.001) and seminal vesicles (p less than 0.05) increased significantly after testosterone replacement therapy. Volume determination of prostate and seminal vesicles by means of transrectal ultrasonography is an available parameter for evaluating the adequacy of testosterone replacement therapy in Klinefelter's syndrome.     

Androgen receptor isoforms in human and rat prostate

Aim: To investigate the androgen receptor (AR) isoforms and its variability of expression in human and rat prostatic tissues. Methods: Human benign prostatic hyperplasia (BPH) and prostatic cancer tissues were obtained from patients undergoing prostatectomy, and rat ventral prostate was incised 3 days after castration. Forty-one AR-positive BPH specimens, 3 prostatic cancer specimens, and 6 rat prostates were used. After processing at 4℃, the tissues were examined by means of high resolution isoelectric focusing (IEF) technique to determine their AR isoforms. Results:From the prostatic specimens, 3 types of AR isoforms were detected with pI values at 6.5, 6.0, and 5.3. In human BPH tissues, 15/41 (36.6%) specimens showed all the three types of isoforms, while 19/41 (46.3%) showed 2 isoforms at various combinations and 7/41(17.1%), 1 isoform. For the 3 prostatic cancer specimens, one showed 3 isoforms, one, 2 isoforms, and the other failed to show any isoform. All rat prostatic tissues showed 2 isoforms at different combinations. Binding of ^3H-dihydrotestosterone (DHT) to the isoforms was inhibited by the addition of 100-fold excess of DHT or testosterone, but not progesterone, oestradiol or diethylstilboestrol. Conclusion: AR isoforms are different in different patients. Although their genesis is not clear, the therapeutic implication of the present observation appears to be interesting, that may help clarifying the individual differences in the response to hormonal therapy.(Asian J Androl 2000 Dec;2:307-310)