Rashad Y. Kirdani

The possibility of aromatization of androgen in human prostate

Aromatase in human prostate tissue was determined in homogenized human prostate (three BPH and two normal specimens) incubated with [1-beta-3H]androstenedione (radiometric method) or [1,2,6,7-3H]androstenedione (estrogen production analysis method) in the presence of NADPH. Using the former procedure, significant amounts of 3H2O, resulting from the release of 3H at the C-1 position during aromatization, were measured and these increased with incubation time and amount of tissue, whereas the amount of estrone and estradiol-17 beta resulting from the latter method and calculated from the 3H/14C ratio in preparations of purified crystal was very small. The preliminary results, which suggest that an androgen aromatase system exists in the human prostate, point to the need to further investigate the identity and properties of the metabolic products resulting from the conversion of androgen to estrogens and other metabolites.

Estrogen receptor protein of pancreas

Abstract A cytosol receptor protein for estriol and estradiol-17β has been demonstrated in the pancreas of the dog, baboon and man. Sedimentation in sucrose gradient revealed this protein to be in 3.7–4.2 S range. The binding capacity of the cytosol was destroyed by proteolytic enzymes, pointing to the protein nature of the binding component. Following incubation of pancreatic tissue at 37°C (but not at 4°) extraction of the washed nuclei with 0.4 M KCl revealed the presence of a protein with a 4.6 S sedimentation characteristic. The findings indicate that specific receptor proteins for estrogens may be present in tissues not considered to be target organs for these hormones.

Inhibitory effects of estracyt on R-3327 rat prostatic carcinoma☆

Estracyt (estramustine phosphate) injected intraperitoneally, 100 mg, per Kg. three days a week for four weeks, retarded growth of the R-3327 tumor in intact rats and in orchiectomized rats given androgen. The growth inhibition was accomplished by reduction of tumor deoxyribonucleic acid concentration and of the activities of acid phosphatase, leucine aminopeptidase, and other hydrolases. Histologic examination revealed cellular necrosis particularly prominent in the orchiectomized, androgen-treated rats. Estracyt did not affect the uptake of 65-Zn in the tumors but markedly reduced the high uptake in the dorsolateral prostate. There was no accumulation of 3H or 14C in the tumors after intravenous administration of 3H, 14C-labeled Estracyt, but the isotope concentrations decreased much in the same way as they decreased in the dorsolateral prostate. The isotopes were retained in the ventral prostate, where their concentrations were approximately twenty times higher than those in the muscle four hours after injection. The results demonstrate the value of the R-3327 tumor in the evaluation of drugs of potential clinical use for the treatment of prostatic cancer. The results also show that Estracyt has an antitumor effect which is not dependent on the antigonadotropic action of the drug.

Steroid hormone receptors in the prostate.

Specific receptors for dihydrotestosterone and estradiol-17-beta have been identified in cytosols of the human and baboon prostate. Binding of radioactive estradiol-17-beta to the 0.4 M potassium chloride extractable component of human prostate nuclei also was demonstrated. Cyproterone acetate and diethylstilbestrol, agents of known high affinity for dihydrotestosterone and estradiol-17-beta receptors, respectively, did not bind significantly to sex hormone binding globulin and, therefore, were useful as competitors in distinguishing binding of dihydrotestosterone and estradiol-17-beta to sex hormone binding globulin and to their specific receptors. Displacement of [3H]-estradiol-17-beta binding by diethylstilbestrol in cytosols of 11 needle biopsy specimens (mean equals 16.8 mg.) from prostatic cancer patients was analyzed. These preliminary data indicated a trend towards greater competition by diethylstilbestrol for high affinity binding sites in differentiated tumor specimens from men who were not receiving estrogen therapy. Objective and subjective responses to hormone therapy were recorded in these patients, whereas the disease in those men with low displacement assay values progressed.

Effects of Diethylstilbestrol and Estramustine Phosphate on Serum Sex Hormone Binding Globulin and Testosterone Levels in Prostate Cancer Patients

Serum testosterone-estradiol binding globulin and total testosterone were measured in 2 groups of male controls (less than 50 and more than 65 years old) and in 7 groups of prostatic cancer patients treated with various endocrine manipulation procedures, including orchiectomy, and estramustine phosphate and diethylstibestrol therapy. There were 133 individuals studied. Total serum testosterone levels were significantly higher in the younger versus the older control group and testosterone-estradiol binding globulin levels were significantly higher in the older men. Whereas orchiectomy reduced serum testosterone to low concentrations (72 plus or minus 11 ng. per 100 ml.) testosterone-estradiol binding globulin levels were not altered. In contrast, estramustine phosphate and diethylstilbestrol therapy, when administered to intact or castrated patients, resulted in depressed testosterone and markedly elevated testosterone-estradiol binding globulin serum levels, particularly in those patients receiving estramustine phosphate (less than 35 ng. per 100 ml. and more than 6 micrograms per 100 ml., respectively). These studies led to the conclusion that diethylstilbestrol or estramustine phosphate therapy is significantly more effective than orchiectomy in eliciting a concomitant elevation of testosterone-estradiol binding globulin and a depression of total testosterone. Even though free serum testosterone was not measured in the present study the law of mass action would indicate that in those patients with high testosterone-estradiol binding globulin (more than 5 microgram. per 100 ml.) and low total testosterone levels (less than 80 ng. per 100 ml.) the availability of biologically active (unbound steroid) testosterone would be negligible.

A comparison of estrogen and androgen receptor levels in human prostatic tissue from patients with non-metastatic and metastatic carcinoma and benign prostatic hyperplasia

Estrogen receptors (ER, N = 72) and androgen receptors (AR, N = 33) were determined by high pressure liquid chromatography (HPLC) in 72 human prostatic tissues obtained at prostatectomy, and exploratory statistical analyses of the resulting data were performed. To facilitate use of these data as well as other pertinent information from the patient charts, a program for a comparatively large data base was implemented on a Wang minicomputer. The median values of cytosolic AR in the four cancer stages examined were statistically different from each other (P = 0.01), with AR increasing from stages A through D. Even though ER differences between the four stages were not significant (P = 0.13), there was a trend, in the data examined, for median ER values to decrease with stages B through D. On the other hand, median BPH values for both ER and AR were found to lie mid-scale compared with the respective cancer stages, leading to the conclusion that receptor measurements probably cannot distinguish between CA and BPH in human prostatic tissue, at least as measured by competitive binding techniques.

Estrogen receptors and clinical correlations with human prostatic disease

Measurement of estrogen binding in human prostate using high-pressure liquid chromatography (HPLC) revealed the presence of cytosolic estrogen receptors (ER) both in benign prostatic hyperplasia (BPH) and adenocarcinoma. Receptor concentrations correlated with several histopathologic features in the specimens analyzed. Estrogen receptor levels generally were higher in BPH than in cancer specimens although there was a subgroup of patients with poorly differentiated carcinoma with levels higher than those of BPH, HPLC can be used for measuring ER in 50 microliters of cytosol, and thus needle biopsy specimens will be analyzed routinely for ER with this micromethod.

Effects of testosterone and estradiol on ventral prostate and body weights of castrated rats

Abstract Administration of 100 μg of testosterone (T) daily for 14 and 28 days to 7-day castrate rats restored the weight of the ventral prostate to a level which slightly exceeded that of the controls. Ventral prostate weight in groups receiving estradiol-17β (E2) doses of 10, 50, 100, 200, or 500 μg administered simultaneously with 100 μg of T did not differ significantly from intact controls, although the weights were lower at E2 levels greater than 100 μg. Body weights of the castrated rats receiving 100 μg of T did not differ from those of sham castrated controls. However, mean body weights of all groups which received E2 (10 to 500 μg) simultaneously with 100 μg of T were significantly less than (p

Estramustine phosphate: metabolic aspects related to its action in prostatic cancer.

Estramustine phosphate, a drug effective in a substantial number of patients with cancer of the prostate who had failed on other forms of therapy, has been shown to be split into its constituents, that is estradiol-17beta and the carbamate nitrogen mustard by non-cancerous and cancerous human prostatic tissues. This fact may explain, in part, the mechanism of action and efficacy of the drug in patients with cancer of the prostate. In addition to presenting results on the hydrolysis and its products accomplished by human prostatic tissues we discuss the limitations of extrapolating animal results with estramustine phosphate to the human condition and possible parameters that bear upon the insignificant toxic and estrogenic effects observed in patients given estramustine phosphate.

Prostatic binding of estradiol-17β in the baboon

A specific receptor for estradiol-17β (E2) has been identified in the caudal and cranial lobes of the baboon prostate. Following in vivo infusion of [3H]-E2 into the hypogastric arteries of castrated and intact baboons, the prostate, particularly the cranial lobe, concentrated more radioactivity than any other tissue or fluid not involved in the metabolism or excretion of E2. Sucrose density gradient centrifugation of in vivo and in vitro labeled cytosols showed that the bound E2 complex had a sedimentation coefficient of ∼-4S. Sephadex G-25 filtration of cytosols and 0.4 M KCl nuclear extracts of caudal and cranial lobe preparations from intact and 40 h castrates infused with [3H]-E2 showed bound radioactivity in all cases. Analysis of nuclear residues resistant to 0.4 M KCl extraction revealed significant concentrations of radioactivity. Testosterone (T) and dihydrotestosterone (DHT) did not compete in vitro with [3H]-E2 for the estrogen receptors, but E2 and diethylstilbestrol (DES) were effective competitors. Nafoxidine, and to some extent estracyt, displaced labeled E2 from cytosol binding sites. Analysis of cytosols and nuclear preparations following in vitro incubations of prostatic tissues revealed further evidence of specific cytosol binding and demonstrated nuclear translocation of a [3H]-E2 bound complex. Scatchard and double reciprocal plots indicated Ka and Ka values for the E2 binding to be about 1.2 × 109 M and 8.3 × 10−10M for the caudal lobe and 7.7 × 109 M and 1.3 × 10−10 M for the cranial lobe, respectively.