Prolactin and luteinizing hormone-releasing hormone receptors in human benign prostatic hyperplasia and prostate cancer

Secretion of prostatic specific antigen, proliferative activity and androgen response in epithelial-stromal co-cultures from human prostate carcinoma

We investigate the proliferative activity, prostatic specific antigen (PSA) secretion, morphology and androgen response of human prostate tumour epithelial cells co-cultured with stromal cells in a bicameral system. Stromal and epithelial cells were isolated from prostate adenocarcinoma by enzyme digestion and cultured in defined media. Immunocytochemistry for prostate carcinoma tumour antigen (PCTA-1) was performed for culture purity evaluation. Also, the morphology of the epithelial cells in co-culture was evaluated by electron microscopy. PSA was determined by microparticle enzyme immunoassay (MEIA) automatized protocol and the proliferation was evaluated by a commercial spectrophotometric kit, based on formazan salt formation. Both cell cultures showed more than 90% of purity. The epithelial cell co-cultures showed marked membrane processes and cell interdigitations. The proliferative activity of the epithelial cells was increased in presence of stromal cells. Also, PSA secretion was significantly increased and maintained for at least 14 days, whereas the androgen response for PSA secretion was evidenced only in co-culture condition. Primary co-cultures of epithelial and stromal cells from human prostate carcinoma are able to maintain, for a prolonged time, proliferative and secretory properties as well hormone response, and represent a valuable tool for cellular and molecular studies on prostate cancer.

Aging-associated changes in gene expression in the ACI rat prostate: Implications for carcinogenesis

BACKGROUND

Prostate cancer is the most frequently diagnosed neoplasm and the second leading cause of cancer-related mortality in men. Although the incidence of prostate cancer increases with age, the link between aging and prostate cancer is poorly understood.

METHODS

Affymetrix oligonucleotide microarrays were used to analyze the mRNA expression levels in the dorsolateral prostates from 6- and 18-month-old ACI rats. Real-time RT-PCR and immunohistochemistry was performed to validate microarray data in a select set of genes.

RESULTS

Microarray analysis revealed changes in gene expression associated with inflammation, oxidative stress, tissue remodeling, and energy metabolism. Most of these changes have been related to increased proliferative status of the prostate, anti-apoptosis, activated stroma, and alteration of the energy metabolism.

CONCLUSIONS

Age-associated alterations in the gene expression profile may put the aging prostate in risk for the initiation, promotion, and progression of neoplastic transformation in both our animal model and humans.

Prolactin stimulates cell proliferation through a long form of prolactin receptor and K+ channel activation

PRL (prolactin) has been implicated in the proliferation and differentiation of numerous tissues, including the prostate gland. However, the PRL-R (PRL receptor) signal transduction pathway, leading to the stimulation of cell proliferation, remains unclear and has yet to be mapped. The present study was undertaken to develop a clear understanding of the mechanisms involved in this pathway and, in particular, to determine the role of K(+) channels. We used androgen-sensitive prostate cancer (LNCaP) cells whose proliferation is known to be stimulated by PRL. Reverse transcriptase PCR analysis showed that LNCaP cells express a long form of PRL-R, but do not produce its intermediate isoform. Patch-clamp techniques showed that the application of 5 nM PRL increased both the macroscopic K(+) current amplitude and the single K(+)-channel open probability. This single-channel activity increase was reduced by the tyrosine kinase inhibitors genistein, herbimycin A and lavandustine A, thereby indicating that tyrosine kinase phosphorylation is required in PRL-induced K(+) channel stimulation. PRL enhances p59( fyn ) phosphorylation by a factor of 2 after a 10 min application in culture. In addition, where an antip59( fyn ) antibody is present in the patch pipette, PRL no longer increases K(+) current amplitude. Furthermore, the PRL-stimulated proliferation is inhibited by the K(+) channel inhibitors alpha-dendrotoxin and tetraethylammonium. Thus, as K(+) channels are known to be involved in LNCaP cell proliferation, we suggest that K(+) channel modulation by PRL, via p59( fyn ) pathway, is the primary ionic event in PRL signal transduction, triggering cell proliferation.

Advancing perspectives on prostate cancer: multihormonal influences in pathogenesis

Nonandrogenic hormones are implicated in the growth and function of the prostate, which is itself an endocrine gland that synthesizes and secretes hormones and growth factors, including follicle-stimulating hormone (FSH) and prostatic inhibin peptide (PIP). Findings of increased FSH concentrations and receptor expression in diseased prostate tissue suggest a role for FSH in prostate cancer growth. Not only does PIP suppress circulating levels of FSH, but it responds to and modulates prostatic FSH, suggesting a close interlinkage of these compounds in controlling both healthy and diseased prostate cells. Other focuses of endocrinologic research include androgen receptors, vitamin D, growth factors (including insulin-like growth factors I and II), and retinoids. Issues such as optimal therapy timing, intermittent administration, and the adoption of a multihormonal approach to the management of prostate cancer remain to be resolved.

Effects of hyperprolactinemia on rat prostate growth: evidence of androgeno-dependence

The effects of the polypeptide hormone prolactin (PRL) in the development and regulation of benign prostate hyperplasia (BPH) and also in prostate cancer are not very well characterized. This study examines the action of PRL, either alone or in association with androgens [testosterone (T) or dihydrotestosterone (DHT)], in the rat prostate gland. The effects of PRL and androgens were investigated after 30 and 60 days in control, castrated, castrated with a substitutive implant of T or DHT, and sham-operated Wistar rats. To enhance PRL release, we induced hyperprolactinemia by administering chronic injections of sulpiride (40 mg. kg(-1). day(-1)). Chronic hyperprolactinemia induces enlargement and inflammation of the lateral rat prostate without any histological changes on ventral and dorsal lobes. We also demonstrate that hyperprolactinemia induces Bcl-2 overexpression in the lateral rat prostate and that this could inhibit the level of apoptosis. The in vivo model established here is a useful in vivo approach for studying the hormonal regulation of normal and pathological prostate development.

Possible direct effect of gonadotropin releasing hormone on human endometrium and decidua

Decidualization of endometrial tissues, which is essential for implantation and the continuation of pregnancy, is induced by pituitary hormones that are regulated by gonadotropin releasing hormone (GnRH). Our objective was to determine the role of a direct action of GnRH on endometrial tissues by comparing the characteristics of receptors for GnRH in human endometrial and decidual tissues. Competitive binding studies were performed with the protease-resistant GnRH analogues, buserelin and [125I] buserelin. The effects of buserelin on phosphoinositol turnover were determined by the measurement of inositol 1,4,5-triphosphate(IP3). The values for the dissociation constant (Kd) and number of binding sites (Bmax) per unit protein versus buserelin for endometrial tissues did not differ from the values for decidual tissues. However, the Bmax per unit DNA was significantly higher in endometrial tissues. Also, buserelin induced a significant increase in IP3 in decidual tissue. These results indicate that GnRH may be a potential modulator of the function in human endometrium and decidua. The signal transduction mechanism for GnRH action appeared to involve the accelerated turnover of phosphoinositol.

Effect of active immunization against luteinizing hormone-releasing hormone on the androgen-sensitive Dunning R3327-PAP and androgen-independent Dunning R3327-AT2.1 prostate cancer sublines

BACKGROUND

The objective of this study was to determine the effect of active immunization against LHRH on the growth characteristics and histology of subcutaneously implanted tumors of the androgen-sensitive Dunning R3327-PAP and androgen-independent R3327-AT2.1 rat prostate adenocarcinoma sublines.

RESULTS

We herein demonstrate that 1) active immunization with an LHRH-diphtheria toxoid-conjugate (LHRH-DT) leads to the downregulation of gonadotropins and testosterone and consequently the atrophy of testosterone-dependent organs such as the testes, prostate, and androgen-sensitive Dunning R3327-PAP tumors, 2) growth inhibition of Dunning R3327-PAP tumors is caused by suppression of cell division rather than by an increase in cell death and is associated with an increase of the tumor stroma content, and 3) volume increase of the androgen-independent Dunning R3327-AT2.1 tumor is slightly but significantly reduced, indicating a local stimulatory LHRH loop within this tumor cell line.

Prolactin regulation of mitochondrial aspartate aminotransferase and protein kinase C in human prostate cancer cells

Citrate production is a major physiological function of the prostate that is regulated by testosterone and prolactin. Mitochondrial aspartate aminotransferase (mAAT) is a key enzyme in the metabolic pathway of prostate citrate production. In addition, prolactin stimulates expression of mAAT in the rat lateral prostate. In this report we establish the role of prolactin in the regulation of mAAT in two prostate cancer cell lines, LNCaP and PC-3. LNCaP cells respond to hormonal stimulation with increased secretion of prostate specific products. PC-3 cells, on the other hand, are testosterone independent and apparently do not respond to other growth factors either. Results showed that both LNCaP and PC-3 cells responded to prolactin with increased mAAT activity and an increased steady state level of mAAT mRNA. Prolactin also increased protein kinase C (PKC) activity in both these cell lines. Treatment of LNCaP and PC-3 cells with the phorbol ester 12-O-tetradecanoylphorbol (TPA) caused the same effect on mAAT activity and mRNA level as prolactin. The results suggest that the diacylglycerol-PKC signal transduction system mediates the prolactin effect on mAAT. In addition, these results also show that the prolactin effect on mAAT is independent of androgens since PC-3 cells reportedly lack androgen receptor expression. Thus, these results provide evidence that prolactin is a physiological regulator of prostate function in human as well as rat prostate. In addition, the results also show that though prostate cancer cells are androgen independent, they remain responsive to prolactin. This could have important implications for the treatment and management of prostate cancer.

Expression of gonadotropin-releasing hormone receptor in human epithelial ovarian carcinoma

We have previously demonstrated the presence of gonadotropin-releasing hormone (Gn-RH) messenger ribonucleic acid (mRNA) in epithelial ovarian carcinoma. In this study, the expression of Gn-RH receptor (Gn-RHR) was investigated in human ovarian carcinoma and human ovarian carcinoma cell line. Gn-RHR was determined by [3H]Gn-RH binding assay. Gn-RHR mRNA was determined by reverse transcription-polymerase chain reaction using oligonucleotide primers synthesized based on published human Gn-RHR sequence. Specific Gn-RH binding sites were shown to be present in plasma membrane isolated from five ovarian mucinous cystadenocarcinoma samples and one serous cystadenocarcinoma (Kd = 15.3 +/- 8.08 nmol/L). Gn-RHR mRNA was detected in four mucinous cystadenocarcinoma specimens, one serous cystadenocarcinoma, and SK-OV-3 cells, but not in white blood cells. These results suggest that Gn-RH may play an autocrine regulatory role in the growth of ovarian carcinoma.

Gonadotropin-releasing hormone receptor in gynecologic tumors. Frequent expression in adenocarcinoma histologic types

BACKGROUND

Gonadotropin-releasing hormone (Gn-RH) analogs have been used in the therapy of the endocrine-dependent cancers. The authors attempted to determine the frequency with which Gn-RH receptor (Gn-RHR) is present in gynecological cancers.

METHODS

Experiments were performed on gynecologic tumors that had been surgically removed and their cloned cell lines. Gn-RHR was characterized by [3H]Gn-RH binding to plasma membrane preparations. Gn-RHR messenger ribonucleic acid was determined by reverse transcription-polymerase chain reaction using oligonucleotide primers synthesized according to the published human Gn-RHR sequence.

RESULTS

High affinity binding sites with nanomolar range of Kd and Gn-RHR mRNA were detected in a high proportion (over 90%) of the specimens from endometrium (6 of 6) and endometrial carcinomas (16 of 17), myometrium (6 of 6) and myomas (4 of 5), epithelial carcinoma (21 of 23), and stromal tumors (3 of 3) of the ovary. There was no substantial Gn-RHR in cervical carcinomas or germ cell-derived tumors of the ovary. Cloned cell lines gave identical results to those obtained in their respective mother tumors.

CONCLUSIONS

We detected Gn-RHR in a wide range of the carcinomas and tissues originating from the endometrium and ovary, but not in the uterine cervix or germ cell-derived tumors. The expression of Gn-RH receptor raises the possibility that Gn-RH may play a direct regulatory role in the growth of these carcinomas, and provides a possible point of attack for therapeutic approaches using Gn-RH analogs in these malignancies.

The effect of active immunization against gonadotropin-releasing hormone on the ultrastructure of the rat ventral prostate

To evaluate the effects of active immunization against gonadotropin-releasing hormone (GnRH) on the ultrastructure of the rat ventral prostate, male Sprague-Dawley rats received three consecutive intramuscular injections of 10 micrograms/100 g body weight (D-Lys6)-GnRH-diphtheria toxoid conjugate (GnRH-DT vaccine). Following immunization, test animals developed sufficiently high antibody titres to block the pituitary gonadal axis. Consequently testosterone values dropped to the levels in castrates. This therapy leads to atrophy of the prostate. Following immunization a strong immunological response, indicating the presence of considerable amounts of a GnRH-like peptide, was observed in the ventral prostates as early as 14 days after the first injection of GnRH-DT. Immunoneutralisation of GnRH-like activity may contribute to the effects observed.

Presence of gonadotropin-releasing hormone and its messenger ribonucleic acid in human ovarian epithelial carcinoma

OBJECTIVE

The purpose of this study was to investigate the expression of gonadotropin-releasing hormone messenger ribonucleic acid and the presence of gonadotropin-releasing hormone in human ovarian carcinoma known to have gonadotropin-releasing hormone binding sites and to be affected by gonadotropin-releasing hormone analog.

STUDY DESIGN

Human ovarian carcinomas surgically removed and human ovarian carcinoma cell lines were examined. Gonadotropin-releasing hormone was determined by a radioimmunoassay and a bioassay. Gonadotropin-releasing hormone messenger ribonucleic acid was determined by reverse transcription polymerase chain reaction using oligonucleotide primers synthesized according to the published human gonadotropin-releasing hormone sequence.

RESULTS

Gonadotropin-releasing hormone was shown to be present in extracts of ovarian mucinous cystadenocarcinoma sample (0.8 +/- 0.12 pg/mg of protein) and ovarian adenocarcinoma cell line SK-OV3 (0.92 +/- 0.17 pg/mg of protein) but not in the normal ovary and placenta. Two of two extract samples from individual cases evoked dose-dependent phosphoinositide breakdown in rat granulosa cells similar to that caused by authentic gonadotropin-releasing hormone. Gonadotropin-releasing hormone messenger ribonucleic acid was detected in two of two mucinous cystadenocarcinoma specimens, one of one serous cystadenocarcinoma, and SK-OV3 cells but not in the dysgerminoma, mucinous cystadenoma, and normal ovary and placenta.

CONCLUSION

The demonstration of gonadotropin-releasing hormone and its messenger ribonucleic acid raises the possibility that gonadotropin-releasing hormone may play an autocrine regulatory role in the growth of ovarian carcinoma.

Failure to detect gonadotrophin-releasing hormone receptors in human benign and malignant breast tissue and in MCF-7 and MDA-MB-231 cancer cells

We have measured the binding of radiolabelled analogues of gonadotrophin-releasing hormone (GnRH) to homogenates of human breast cancer and benign breast tissue, and to MCF-7 and MDA-MB-231 cell lines. Although incubation of breast cancer homogenates with the 125I-labelled GnRH agonist analogues, buserelin [(D-Ser tBU6)GnRH 1-9 ethylamide] and tryptorelin [(D-Trp6) GnRH 1-9 ethylamide] appeared to show significant though low, specific GnRH agonist binding in a high proportion of breast cancers (32/42 for buserelin; 15/32 for tryptorelin) and benign breast tissues (13/16 for buserelin; 10/12 for tryptorelin), after correction for displaceable binding in control assay tubes, GnRH agonist binding to breast tissue was no longer apparent. The lack of specific binding was not due to inactivation of GnRH agonist tracers, as > 86% of the unbound tracer was still capable of rebinding to fresh placental membranes after incubation with breast cancer homogenates. GnRH agonist did not bind to MCF-7 and MDA-MB-231 cells, however GnRH agonist tracer inactivation following exposure to these cells was very high. We have shown recently that human placental receptors bound salmon GnRH and chicken GnRH II as well as GnRH agonists, but not other isoforms of GnRH. However, no isoform of GnRH bound significantly to human breast tumour tissue. In summary, we could not confirm the presence of specific GnRH binding sites in homogenates and membranes from human breast tissues in this study. Low levels of apparently specific binding of GnRH agonist tracers could be accounted for entirely by displacement of tracer from assay tubes. Inability to demonstrate specific binding was not due to extensive inactivation of GnRH tracers (although this may be a factor in the failure to demonstrate GnRH binding to MCF-7 and MDA-MB-231 cell lines).

Concepts of citrate production and secretion by prostate: 2. Hormonal relationships in normal and neoplastic prostate

A unique and major function of prostate secretory epithelial cells is to synthesize, accumulate, and secrete extraordinarily high levels of citrate. This function is regulated by testosterone and by prolactin. Concepts of the mechanisms of hormonal regulation are presented. The relationship of testosterone and prolactin to the origin and homologies of different prostate cell lines is described. The metabolic differentiation of citrate and non-citrate producing prostate secretory epithelial cells is discussed. Concepts of the pathogenesis of prostatic neoplasms are presented based on hormonal, metabolic, and homologous relationships associated with citrate production. Characterization of normal and neoplastic secretory epithelial cells by their citrate function is emphasized. The urgency and necessity for research relating to all aspects of prostate citrate production in normal and pathological prostate are emphasized.

Presence of membrane binding sites for [D-TRP6]-luteinizing hormone-releasing hormone in experimental pancreatic cancer

Characteristics of binding sites (dissociation constant: Kd and maximal binding capacity: Bmax) for [D-Trp6]-luteinizing hormone-releasing hormone [( D-Trp6]-LH-RH]), somatostatin (SS-14) and epidermal growth factor (EGF) were evaluated in membrane fractions of N-Nitrosobis (2-oxopropyl) amine (BOP)-induced pancreatic adenocarcinoma of hamsters. Intact, normal hamster pancreata did not show any binding sites for [D-Trp6]-LH-RH, but specific [D-Trp6]-LH-RH binding sites with low affinity and high capacity were found after pancreatic cancer was induced with BOP. Membrane binding sites for SS-14 and EGF, with high affinity and low capacity were present, both in normal and cancerous pancreata. Normal hamster pancreatic tissue had significantly higher levels of SS-14 binding sites and lower concentration of EGF binding sites as compared to pancreatic carcinoma. In vivo treatment of hamsters bearing pancreatic cancers with microcapsules of agonist [D-Trp6]-LH-RH and the somatostatin analog RC-160 alone, or in combination, caused histopathological regression of tumors and concomitantly decreased the Kd and Bmax of [D-Trp6]-LH-RH, and increased the Bmax of the SS-14 binding sites. These findings represent the first demonstration of binding sites for [D-Trp6]-LH-RH in pancreatic cancers. Our results also suggest that tumor inhibitory effects of [D-Trp6]-LH-RH and RC-160 in pancreatic cancer could be mediated not only indirectly through suppression of sex-steroids, gastrointestinal hormones and growth factors, but also directly by an action on specific binding sites located on the tumor membranes.

Characteristics and distribution of receptors for [D-TRP6]-luteinizing hormone-releasing hormone, somatostatin, epidermal growth factor, and sex steroids in 500 biopsy samples of human breast cancer

Binding capacities and apparent dissociation constants of receptors for [D-Trp6]-luteinizing hormone-releasing hormone [( D-Trp6]-LH-RH), somatostatin (SS-14), epidermal growth factor (EGF), and estrogen and progesterone were determined in 500 breast cancer specimens using multipoint assays. Specific binding sites greater than 10 fmol/mg cytosol protein for estrogen were found in 408 carcinomas (81.6%), and for progesterone in 340 specimens (68%). High affinity EGF receptors were present in membrane preparations from 335 samples (67%). In 260 of 500 samples (52%), two classes of [D-Trp6]-LH-RH membrane receptor sites were also detected, one class showing high affinity and low capacity, and the other class showing low affinity and high capacity; 178 biopsy samples (35.6%) exhibited binding sites for SS-14. Statistically significant inverse correlations were found between the binding capacities of estrogen and EGF receptors as well as between Bmax of progesterone and EGF receptors. Significant positive correlations were demonstrated between binding capacities of estrogen and progesterone and between Bmax of high affinity and low affinity binding sites of [D-Trp6]-LH-RH receptors. However, no correlation was found between the dissociation constants of different receptor sites in human breast cancer specimens. These results demonstrate that numerous human breast cancers, in addition to receptors for estrogen and progesterone, also show binding sites for EGF, [D-Trp6]-LH-RH and SS-14. The methods described herein permit a routine quantification of receptor sites for [D-Trp6]-LH-RH, SS-14, and EGF in membrane preparations of biopsy samples of breast cancer and can be used in conjunction with the determination of estrogen and progesterone receptors in nuclear-cytosolic extracts. The simultaneous measurements using a microanalytic approach allow the determination of peptide and steroid hormone receptors that might be involved in the response mechanisms of human breast cancer. It should be possible to correlate the levels of these receptors with clinical parameters to better identify endocrine-responsive neoplasms. This approach might be useful to guide a rational hormonal therapy in women with breast cancer.

Receptors for luteinizing hormone-releasing hormone, somatostatin, prolactin, and epidermal growth factor in rat and human prostate cancers and in benign prostate hyperplasia

Using sensitive multipoint micromethods, we estimated membrane receptors for [D-Trp6]-luteinizing hormone-releasing hormone ([ D-Trp6]-LH-RH), somatostatin (SS-14), human prolactin (hPRL), and epidermal growth factor (EGF) in experimental Dunning rat prostate cancers and in samples of normal human prostate, benign prostatic hyperplasia (BPH), and human prostate cancer (PC) obtained from biopsy, after prostatectomy, or at autopsy. In the Dunning R-3327 rat prostate adenocarcinoma specimens, the receptors were characterized in untreated animals and following in vivo treatment with microcapsules of the agonist [D-Trp6]-LH-RH and the somatostatin analog RC-160. Two populations of binding sites were found for [D-Trp6]-LH-RH, one with high affinity and low capacity and another with low affinity and high capacity. Treatment with [D-Trp6]-LH-RH and RC-160 alone or with the combination of these analogs increased the binding capacity (Bmax) of the low-affinity binding sites for [D-Trp6]-LH-RH and decreased Bmax for hPRL and EGF. Therapy with [D-Trp6]-LH-RH also reduced Bmax of SS-14 binding and dissociation binding constant of high-affinity binding sites for [D-Trp6]-LH-RH, whereas administration of RC-160 or the combination treatment with both analogs increased Bmax of SS-14 binding. These findings are compatible with the view that analogs of LH-RH and SS-14 might exert some direct inhibitory effects on the Dunning prostate cancer. Among 13 human BPH samples examined, only one had receptors for [D-Trp6]-LH-RH, and seven specimens exhibited binding for prolactin. [D-Trp6]-LH-RH receptors were found in all seven samples of human PC but not in any of the eight specimens of normal human prostate. All samples of normal human prostate, BPH, and human PC exhibited binding sites for EGF but not for SS-14. Our findings on the membrane receptors in the human and rat prostate cancers raise the intriguing possibility that LH-RH, acting as a growth factor, along with EGF and prolactin, might be involved in complex interactions that contribute to the promotion of prostate cancer in man.

Inhibition of the pituitary-gonadal axis by a single intramuscular administration of D-Trp-6-LH-RH (decapeptyl) in a sustained-release formulation in patients with prostatic carcinoma

For the past 6 years we used daily injection of luteinizing hormone-releasing hormone (LH-RH) agonists to treat patients with advanced prostate carcinoma. In this study we determined the hormonal response of the pituitary-testicular axis over a 2-month period and evaluated the safety and tolerance of the single intramuscular administration of sustained-release formulations of D-Trp-6-LH-RH microcapsules designed to release 50, 100, or 200 micrograms/day for over 1 month. Serum levels of LH, testosterone, and D-Trp-6-LH-RH were measured by RIA for up to 60 days in 10 patients with advanced prostatic carcinoma who had not received any previous drug therapy. After the administration of the microcapsules there was a biphasic increase in D-Trp-6-LH-RH serum levels. The maximal peak was obtained between 1 and 3 hr, and a second peak occurred between weeks 4 and 6. LH levels increased initially, with a maximal peak at 60 min, and elevated serum LH values persisted for more than 24 hr. LH levels began to fall on the second day, reaching subnormal values after 1 week. Serum testosterone rose during the first week and fell subsequently to less than 100 ng/dl. A rebound in LH and testosterone was seen about the 50th day after the microcapsule administration. Following the first week of therapy, we observed in all patients a significant decrease in bone pain, improvement in urinary flow obstruction, and a reversal of the signs of prostatism. No side effects were observed, and acceptance of the microcapsules was very good. Our results show that a single dose of D-Trp-6-LH-RH microcapsules suppresses of the pituitary-testicular axis for at least 50 days. D-Trp-6-LH-RH microcapsules facilitate the treatment and should lead to an improvement in the therapeutic response.