Preliminary studies on the isolation and characterization of predominant prostatic proteins.

BACKGROUND: The increasing incidence of prostate cancer demands that we give our full attention not only to the etiology and prevention of this common type of cancer, but also to the diagnosis and prognostic course of this disease. In an effort to develop new prostatic tumor markers that could be useful to the physician at the current state of our knowledge in the diagnosis and prognosis of this disease, our laboratories have undertaken an effort to isolate and characterize the nature of the major proteins in the normal prostate and in prostatic neoplasia. METHODS: In this preliminary study, tissue was obtained from open prostatic surgery in patients with a pre- and postoperative diagnosis of benign prostatic hyperplasia. The initial fractionation and separation of the proteins was achieved through the use of ultrafiltration of homogenates followed by SDS-PAGE. Initial analysis of four prominent protein bands was accomplished by amino acid sequencing, and identified by a search in GeneBank data base. RESULTS: Two proteins previously identified in prostatic tissue were prostate specific antigen (M(r) 26,496) with 240 amino acid residues and beta-inhibin (M(r) 10,704) with 94-amino acid residues. A third protein was identified as human cysteine rich protein (hCRP). This protein functions as a DNA binding protein and has previously been postulated to contain four putative zinc fingers and to play a fundamental role in cellular function. Ubiquitin, the fourth major protein identified was a 76-amino acid polypeptide whose function is to target other proteins for destruction. CONCLUSIONS: hCRP and ubiquitin are reported as being found in high levels in prostatic tissue for the first time.

Testicular androgens in prostate cancer patients treated with a luteinizing hormone releasing hormone agonist.

Luteinizing hormone releasing hormone agonists have been shown to reduce the levels of androgens in the peripheral circulation and to reduce prostate volume. The objective of this study was to quantify testicular function in patients with metastatic carcinoma of the prostate treated with a luteinizing hormone releasing hormone agonist, leuprolide, by analysis of spermatic vein blood for testosterone and androstenedione, and by determination of the maximum velocity of the 17 beta-hydroxysteroid oxidoreductase enzyme in testicular tissue in vitro. A chemical analysis of the spermatic vein blood of 19 patients with a median age of 78 years revealed the presence of significantly high levels of testosterone and androstenedione, 20.7 +/- 1.9 micrograms % and 6.7 +/- 0.7 micrograms %, respectively. These androgens could not be detected in patients treated with leuprolide before orchiectomy. Patients treated with leuprolide for several months followed by a period of no treatment before orchiectomy secreted testosterone and androstenedione levels comparable to the control group. The maximum velocity of the 17 beta-hydroxysteroid oxidoreductase enzyme in vitro in the testes of the leuprolide treated patients was significantly inhibited. Enzyme activity returned to normal levels when leuprolide treatment was followed by a recovery period of no treatment before orchiectomy.

In vitro studies on the inhibition of testosterone synthesis in the human testis by atamestane.

In view of the well established clinical results of the deprivation of androgens through orchiectomy in prostatic cancer and the structural similarities of 4-androsten-3,17-dione and atamestane (1-methyl-ADD), we studied the influence of 1-methyl-ADD on the conversion of 4-androsten-3,17-dione to testosterone by the 17 beta-hydroxysteroid reductase enzyme in human testicular tissue. Our studies, presented in this manuscript, demonstrate that 1-methyl-ADD is a competitive inhibitor of 4-androsten-3,17-dione in its reduction to testosterone by the 17 beta-hydroxysteroid reductase enzyme in the human testis.

A study of androgen biosynthesis by the human testis in vitro.

The biosynthetic pathways in human testicular tissue have been studied extensively in our laboratory without the use of radioisotopes. Experiments were conducted with normal testicular tissue from patients undergoing orchiectomy for prostatic cancer. These studies have shown that the preferred pathway of testosterone biosynthesis is influenced by the nature and concentration of cofactor added to the incubation medium. Four enzymes are involved in the transformation of pregnenolone to testosterone, that is, 3 beta-hydroxysteroid dehydrogenase, 17 alpha-hydroxylase, C17-C20 lyase and 17 beta-hydroxysteroid oxidoreductase. Our studies show that the 4-ene pathway predominates in the biosynthesis of testosterone from pregnenolone. Analysis of several samples of human testicular vein blood supports the contention that 4-androsten-3,17-dione is the immediate precursor of testosterone.

In vitro studies on the effect of cofactors on the 5 alpha-reductase and 3 alpha- and 3 beta-hydroxysteroid reductase activities in the hyperplastic human prostate.

Many studies have intimated that the accumulation and hence elevation of dihydrotestosterone (DHT) in the human prostate may be the primary factor in the development of benign prostatic hyperplasia (BPH). This accumulation has been explained in terms of an increase in the 5 alpha-reductase enzymatic activity which converts testosterone to DHT and a decrease in the relative activities of the 3 alpha-HSORred and 3 beta-HSORred enzymes. To investigate this hypothesis further, the activities of these two enzymes were studied in the presence and absence of NADPH in benign hyperplastic tissue and in normal peripheral (NPR) and benign hyperplastic periurethral (BPH) tissue taken from the same prostate. The results of these studies demonstrate a several fold increase in the activities of 3 alpha-HSORred and 3 beta-HSORred in the presence of NADPH in the hyperplastic human prostate. This increase in the activities of these two enzymes is found to the same degree in normal peripheral and benign hyperplastic periurethral tissue taken from the same prostate. There was no difference in percent increase in 3 alpha- and 3 beta-diol formation from DHT with NADPH in normal peripheral versus benign hyperplastic periurethral prostatic tissue. In subsequent experiments, Vmax/Km, as an index of the enzymatic capacity of the 3 alpha-HSORred and 3 beta-HSORred enzymes, was determined in both NPR and BPH tissue in media fortified with one mM NADPH. This quotient was found to be essentially the same in NPR and BPH tissue for both the 3 alpha-HSORred and the 3 beta-HSORred. Subsequently, the Vmax/Km value for the 5 alpha-reductase in BPH tissue was found to be equal to the combined Vmax/Km values of the 3 alpha-HSORred and 3 beta-HSORred. The reverse reaction or the conversion of 5 alpha-androstane-3 alpha,17 beta-diol and 5 alpha-androstane-3 beta,17 beta-diol is completely blocked in a medium containing one mM NADPH. These studies suggest that the concentration of DHT in prostatic tissue is dependent on the level of NADPH necessary for the 3 alpha-HSORred and 3 beta-HSORred enzymes to convert DHT to its respective diols.

Social class and carcinoma of the prostate.

Three thousand, six hundred and four patients with carcinoma of the prostate attending the Royal Marsden Hospital, St Peter's Hospitals and all non-teaching hospitals of the South Metropolitan regions were reviewed, in addition, data from 1869 cases of prostatic carcinoma registered in the 2 South Metropolitan regions with determinable social class were compared with data collected from both teaching and non-teaching hospitals. Carcinoma of the prostate showed an increased incidence with decreasing socio-economic class.

Ultrastructure of the normal human urethra.

The normal ultrastructure of the prostatic, bulbar and penile urethra in the human is described. The human urethra contains both exocrine and what appear to be endocrine glands. Further study is in progress to define the nature and role of the secretion from these endocrine glands.

A new self-retaining catheter with triple microtip pressure transducer: the Baghdad modification.

A new self-retaining triple microtip pressure transducer on a silicone rubber catheter was assessed on 12 patients with bladder neck obstruction or obstruction at the distal urethral component (external sphincter). The catheter gave reliable and accurate information on pressures in the bladder, prostatic and bulbar urethras simultaneously. It is, however, an expensive piece of equipment and requires delicate handling.

The use of fine double siliconised dacron in urethral replacement.

A knitted Dacron mesh was used to form a tube of tissue which was used to bridge at least 5-cm defect in the urethra of 9 dogs. The tube developed a urothelial lining and this showed no change in calibre after 7 months.

Light and electron microscopy study on urethral regeneration.

In a series of experiments on dogs, it was feasible to replace a segment of urethra using wide-mesh Dacron. Light and electron microscopy study on the regenerated urethra showed no evidence of muscle, cavernous tissue and nerve regeneration. Although an excess of fibrous tissue surrounded the regenerated urethra, there was no change in the calibre of the new urethra after 7 months' observation.