nafarelin and Prostatic-Hyperplasia

Efficacy of a slow-release gonadotropin-releasing hormone (GnRH)-agonist implant (Gonazon) was assessed in 53 male dogs presented with benign prostatic hyperplasia (BPH), hypersexuality, aggressive behavior (either alone or in combination), excessive micturition, or to suppress fertility. Changes in testosterone (T) and estradiol (E2) concentrations and size of testes and prostate were monitored on Weeks 0, +8, and +26 after implantation. Additional measurements during and after this period were performed in 35 dogs. Clinical signs were assessed by the owners. All implants except one were retained throughout the study. Full downregulation of testicular function (T<0.35 nmol/L) was achieved in 46 dogs, five dogs showed partial downregulation (T = 0.36 to 0.47 nmol/L), one dog did not respond, and another one displayed a transient downregulation on Week +18. On Week +8, mean T and E2 levels were reduced by 96% and 62%, respectively, and did not further decrease. Full downregulation (T<0.35 nmol/L) lasted between 6 to >22 mo in most dogs except two. Compared with pretreatment values, mean testicular and prostatic size was reduced (P<0.00001) by 54% and 52%, respectively, on Week +8 and by 68% and 64%, respectively, on Week +26. Relative reduction of prostatic size was more marked in dogs with BPH than in healthy ones on Week +8 (P<0.05) and Week +26 (P<0.02), and clinical signs of BPH disappeared rapidly after implantation. Dogs affected with BPH were significantly older (P<0.001) than nonaffected ones (9.7 vs. 2.5 yr). Hypersexuality was more common in dogs<3 yr of age, and treatment clearly improved clinical signs. Age significantly affected the response to treatment in aggressive dogs; 75% of the cases responded with an improvement. The only minor and possibly treatment-related events observed were a short-lasting exacerbation of clinical signs of BPH (two dogs), increased weight gain (three dogs), and anxiety (three dogs) with one of these dogs developing a blunt coat. These results demonstrate the clinical efficacy and overall safety of the Gonazon implants.

Topics: Aggression; Animals; Behavior, Animal; Contraceptive Agents, Male; Dog Diseases; Dogs; Drug Implants; Gonadotropin-Releasing Hormone; Male; Nafarelin; Prostate; Prostatic Hyperplasia; Sexual Behavior, Animal; Testis; Urination

To examine the role of testosterone in the maintenance of hemoglobin levels, we studied the effect of reversible androgen deprivation on hemoglobin, serum immunoreactive erythropoietin, and serum testosterone in seven men treated with a luteinizing hormone-releasing factor (LHRH) agonist for 6 months and then followed for an additional 6 months. The mean serum testosterone level was 4.35 +/- 1.05 ng/ml initially and it decreased to castrate levels in all patients by 6 months. After stopping therapy, there was a rapid increase in serum testosterone such that by 12 months the mean concentration was normal. The pretreatment hemoglobin was 15.2 +/- 0.9 g/dl (mean +/- SD); after 6 months of androgen deprivation it had fallen to 14.1 +/- 0.4 g/dl (P less than 0.05). Six months after stopping therapy, the hemoglobin rose to pre-treatment levels. Before treatment, serum immunoreactive erythropoietin was 9.5 +/- 4.6 mu/ml (mean +/- SD) and did not change significantly during or after the 6 month period of androgen deprivation. No significant inhibition of burst-forming unit-erythroid (BFU-E) or colony-forming unit-granulocyte macrophage (CFU-GM) was observed at the serum level of nafarelin acetate obtainable in vivo. These data suggest that, within the normal range of hemoglobin in men, androgens are a determinant of the red cell mass.

Topics: Aged; Androgens; Erythropoietin; Gonadotropin-Releasing Hormone; Hemoglobins; Humans; Injections, Subcutaneous; Male; Middle Aged; Nafarelin; Prostate; Prostatic Hyperplasia; Radioimmunoassay; Testosterone; Time Factors

This study was designed to investigate the relationship of serum prostate-specific antigen to prostatic size and hormonal stimulation. Seven patients with benign prostatic hyperplasia were treated for six months with nafarelin acetate and then followed for an additional six months. Nafarelin acetate is a potent luteinizing-hormone-releasing hormone agonist which causes reversible testosterone deprivation resulting in involution of the prostate. During therapy and follow up, serum prostate-specific antigen correlated with: 1) serum testosterone (p less than 0.001); 2) quantity of prostatic epithelium (p less than 0.001); and 3) prostatic size (p less than 0.05). Before therapy, serum prostate-specific antigen (mean +/- SD) was 0.43 +/- 0.2 ng./ml. per gram of epithelium. This did not change significantly after six months of androgen deprivation (0.48 +/- 0.36), although the ratios of prostate-specific antigen to testosterone and to prostatic size each changed significantly. Despite testosterone levels in the castrate range at six months, five of seven patients had serum prostate-specific antigen concentrations above the female range and three of seven patients had prostatic biopsies containing columnar epithelium which stained positively for prostate-specific antigen. These results demonstrate that serum prostate-specific antigen is related to prostatic size, prostatic epithelial weight, and testosterone stimulation. However, prostatic size is not a good predictor of serum prostate-specific antigen because there is tremendous variation in the relative amount of epithelium in a prostate; in this study the ratio of prostatic size to epithelial weight varied threefold. Furthermore, although testosterone determines prostatic size and amount of prostatic epithelium, it may not totally control prostate-specific antigen production.

Topics: Aged; Antigens, Neoplasm; Follow-Up Studies; Gonadotropin-Releasing Hormone; Humans; Male; Middle Aged; Nafarelin; Organ Size; Prostate; Prostate-Specific Antigen; Prostatic Hyperplasia; Testosterone; Time Factors

Topics: Gonadotropin-Releasing Hormone; Humans; Male; Nafarelin; Prostatic Hyperplasia

We examined the influence of androgens on benign prostatic hyperplasia, using nafarelin acetate, a potent luteinizing-hormone-releasing hormone agonist, to achieve reversible androgen deprivation in men with benign prostatic hyperplasia. Nine patients with bladder-outlet obstruction due to benign prostatic hyperplasia were treated with subcutaneous nafarelin acetate (400 micrograms per day) in an open trial for six months. In all patients, serum testosterone decreased to castrate levels. Objective observations included uroflowmetry, measurement of residual urine volume, determination of prostatic size by ultrasonography, and prostatic biopsy. In all patients, the prostate regressed to a mean (+/- SEM) of 75.8 +/- 3 percent of the initial size (range, 52 to 86; P less than 0.005); the regression reached a plateau after four months. Morphologic analysis of biopsy specimens showed regression of glandular epithelium. Three of nine patients had clinical improvement with treatment. Six months after the cessation of treatment, plasma testosterone levels had returned to normal and the size of the prostate had increased to 99 +/- 5.5 percent of the initial size. These findings suggest that androgens have an important supportive role in established benign prostatic hyperplasia and that testicular suppression will benefit some patients. However, this form of treatment could be applicable only in carefully selected patients who were not surgical candidates, and it would need to be maintained indefinitely.

Topics: Aged; Gonadotropin-Releasing Hormone; Humans; Injections, Subcutaneous; Male; Middle Aged; Nafarelin; Prostate; Prostatic Hyperplasia; Testis; Testosterone; Urinary Bladder Neck Obstruction; Urodynamics