Effects of short-term oral letrozole on fresh semen parameters, endocrine balance, and prostate gland dimensions in domestic dogs.

BACKGROUND: Aromatase inhibitors improve male fertility by modifying the hormonal control of spermatogenesis. The present study aimed to investigate the effects of oral administration of letrozole on testosterone and estradiol concentrations and their ratios in blood serum, seminal plasma, prostatic fluid, sperm quality in fresh semen, and prostate gland dimensions. Seven adult male intact mixed-breed dogs were selected. The animals received letrozole (72 µg/kg, PO) daily for four weeks. Blood samplings and semen collections were carried out on days 0 (control), 14 (treatment), 28 (treatment), and 42 (post-treatment). RESULTS: Our results showed that letrozole administration resulted in a 4.3 fold significant increase in serum, seminal plasma, and prostatic fluid testosterone levels after 14 days. This remained high until the end of the study. Serum and prostatic fluid estradiol levels did not change significantly over the study period. However, the seminal plasma estradiol level showed a significant increase on day 14. The estradiol: testosterone ratio was significantly reduced on day 14 in serum, seminal plasma, and prostatic fluid samples. Letrozole significantly improved the ejaculated spermatozoa viability and concentration after 28 days of oral administration. However, the sperm plasma membrane functional integrity and kinematic parameters were not significantly affected by the treatment. Transabdominal ultrasound examination revealed a significant increase in the height, width, and volume of the prostate gland after 28 days of treatment. CONCLUSIONS: According to the present research, oral administration of letrozole for 28 days affects local and systemic sex hormone balance leading to an improvement of the ejaculated canine spermatozoa viability and concentration concurrent with an increase in the prostate gland dimensions.

Echotexture Analysis of Prostate Parenchyma for Detection of Benign Prostatic Hyperplasia in Dogs.

Ultrasonography is one of the most common methods for the diagnosis of prostate disorders, such as benign prostatic hyperplasia (BPH), in dogs. Changes in the echotexture are one of the indicators used to diagnose prostate disorders. The purpose of this study was to investigate the changes occurred in the dogs' prostate echotexture during the induction of BPH using image analysis. Twenty sexually mature male intact mixed-breed dogs were selected and divided randomly into control and BPH-induced groups. BPH was induced using testosterone and estrogen injections for 63 days. The ultrasound imaging of the dogs' prostate was performed during the induction of BPH on days 0, 21, 42, and 63. The echotexture of the prostate parenchyma was analyzed using the Image J software. Then, the changes in the echotexture and its correlation and linear regression with the prostate volume and canine prostate specific esterase (CPSE) concentration were evaluated by statistical tests. The prostate parenchyma echotexture did not show any significant changes during the induction of BPH and in comparison with that of the control group. While prostate volume and CPSE concentration increased significantly, indicating that BPH was induced in the dogs. There was no significant correlation and linear regression between the prostate echotexture and prostate volume or between the CPSE concentration and prostate echotexture. According to the results, the alteration in the prostate parenchymal echotexture did not occur in the early stages of induced BPH, but significant changes occurred in the prostate volume and CPSE concentration during those early stages.

Changes in the Serum Prostatic Biomarkers During the Treatment of Benign Prostatic Hyperplasia with a 5alpha-reductase Inhibitor: Finasteride.

The monitoring of serum prostatic biomarkers during the treatment will help clinicians to know the statement of the response to finasteride in dogs affected by benign prostatic hyperplasia (BPH). The present study was aimed to assess changes in the serum canine prostate-specific esterase (CPSE), prostate-specific antigen (PSA), prostatic acid phosphatase (PAP), testosterone, dihydrotestosterone (DHT) and prostate volume evaluation using ultrasonographic examination during the treatment with finasteride in BPH-induced dogs. Twenty dogs were divided into 4 groups (n = 5): BPH + finasteride group, dogs which were induced for BPH and received oral finasteride once daily for 1 month; BPH group, dogs which were induced for BPH and received placebo; finasteride group, normal dogs which received finasteride; and normal group, normal intact dogs which did not receive treatment. Blood sampling and ultrasonography examination were performed on days 0, 14, and 28. The administration of finasteride led to a significant decrease in the concentration of the prostate-specific biomarkers (PSA, CPSE), DHT, testosterone, and the volume of the prostate in BPH + finasteride group compared with the BPH group during 1 month. Interestingly, the PAP concentration did not change in the BPH-induced dogs and in dogs treated with finasteride. It seems that the monitoring of serum PSA and CPSE levels and ultrasonographic examination of the prostate are useful methods for following up the response to finasteride treatment in dogs affected by BPH.

Changes in specific serum biomarkers during the induction of prostatic hyperplasia in dogs.

BACKGROUND: Prostatic hyperplasia (PH) is one of the most important disorders in intact dogs. In this study, we aimed to induce PH experimentally using the combination of testosterone and estrogen and evaluate important factors associated with this disease. RESULTS: The results showed that in the induction group, prostate volume and prostate specific antigen (PSA) concentration increased significantly on day 21 onwards compared to those of the control group. Canine prostatic specific esterase (CPSE) and dihydrotestosterone (DHT) concentrations increased significantly on day 42 onwards while the testosterone levels increased on day 63. In addition, prostatic acid phosphatase (PAP) concentration did not change significantly in the control and induction groups. Biochemistry profiles and hematologic factors were measured for monitoring the function of liver and kidney, and there were no adverse effects following the induction of PH. CONCLUSIONS: It seems that testosterone and estrogen administration led to prostatic hyperplasia during 2 months. Investigating the size of the prostate, accompanied by prostate markers including CPSE, PSA, DHT, and testosterone, is helpful for the PH diagnosis. However, further studies should be carried out on PAP.