High Plasma Estradiol-17.BETA. Levels in Dogs with Benign Prostatic Hyperplasia and Azoospermia.

Abstract

ABSTRACT. The semen quality of 22 dogs (4 to 7 years old) with benign prostatic hyperplasia (BPH) was examined at the hospital of our university, and 4 of the 22 BPH dogs were diagnosed as azoospermic. The mean peripheral plasma estradiol-17β (E 2 ) level (17.3 pg/ ml) of the 18 BPH dogs with spermatogenic function was higher than that of 5 normal male dogs and their mean T level (1.7 ng/ml) was lower. The mean E 2 level (27.3 pg/ml) of the 4 BPH dogs with azoospermia was significantly higher than the value in the BPH dogs with spermatogenic function (P<0.01), and the mean T level (1.1 ng/ml) was significantly lower (P<0.05). Five normal male dogs were given 10 intramuscular injections of estradiol benzoate (E 2 B) 5 µg/kg, at 3-day intervals to investigate the relationship between high plasma E 2 levels and the cause of the BPH and azoospermia. Their testes and prostates were measured and biopsied both before and 30 days after the start of E 2 B injections. At 30 days after the start of the E 2 B injections, the mean peripheral plasma T levels had decreased by half, and the mean testicular volume had decreased to 88% of original volume. The numbers of spermatocytes, spermatids, and spermatozoa in the seminiferous tubules of all of the dogs were significantly lower (P<0.05, 0.01). In addition, the mean prostatic volume increased to 130%, the mean height of the glandular epithelium decreased, and the glandular lumen became increased in diameter. These findings indicate that both BPH and serious spermatogenic dysfunction may be simultaneously induced by protracted high plasma E 2 levels in dogs. KEY WORDS: azoospermia, benign prostatic hyperplasia, canine, estradiol-17β.J. Vet. Med. Sci. 63(4): 407-412, 2001 Canine benign prostatic hyperplasia (BPH) in dogs is known to occur chiefly in animals more than 6 years old [6], and its occurrence is presumed to be associated with abnormal estradiol-17β (E 2 ) and testosterone (T) secretion by the testes associated with advanced age [5,19]. T is converted to 5α-dihydrotestosterone (DHT) in the canine prostate, and prostatic function is maintained by the androgen effects of DHT [10,11]. DHT concentration in the prostates of dogs with BPH has been reported to be higher than in normal dogs [8,14]. Accumulation of DHT in the prostate is accelerated by high plasma E 2 levels and is thought to cause BPH [8,14].Testicular and plasma E 2 are produced by both Leydig cells and Sertoli cells [23]. Infertility in a few human patients has been attributed to elevated testicular E 2 concentrations [13], and the plasma E 2 levels of some azoospermic men have been found to be higher than those of normal men [9,29]. Long term E 2 administration has been shown to inhibit T secretion by the testis in rats [28], to cause the disappearance of spermatids and spermatozoa from the seminiferous tubules of bull testes [21], and to induce the testicular atrophy of dogs [15]. However, in many cases the cause of spermatogenic arrest in dogs is unknown [7,24]. In the present study, the peripheral pla...

Reproductive and endocrinological effects of Benign Prostatic Hyperplasia and finasteride therapy in dogs

“…Tubes were immediately centrifuged at 1,500×g for 10 min and serum was drawn-off and stored in microtubes at − 20 °C until analysis. www.nature.com/scientificreports/ Hormonal assays were performed with the use of commercial radioimmunoassay kits for quantitative measurement of testosterone and estrogen (Beckman Coulter®), previously validated for dogs 51,52 , and competitive ELISA kits for dihydrotestosterone assay 53 , previously validated for dog. For estradiol, the intra-assay coefficients were 7.15% (high intra-assay) and 3.45% (low intra-assay) and the limit detection was 1.12 pg/mL.…”

Prostatic hyperplasia: Vascularization, hemodynamic and hormonal analysis of dogs treated with finasteride or orchiectomy

“…Testosterone and estrogen concentration was measured using a commercial radiomunoassay kit (BECKMAN Coulter Company IM-1841 / IM-1119-Immunotech, Prague, Czech Republic and BECKMAN Coulter Company IM-1841 / DSL4800-Immunotech, Prague, Czech Republic, respectively), both previously validated for dogs [13,27] For dihydrotestosterone, competitive ELISA kit (BECKMAN, Active1 DSL9600i-Immunotech-, Prague, Czech Republic) was used [28]. The limit detection for the testosterone assay was 0.01 ng/mL and the intraassay coefficient of variation was 4.52%.…”

Therapeutic Effect of Aromatase Inhibitor in Two Azoospermic Dogs with High Plasma Estradiol-17&beta; Levels

“…In the testes of many species [2,17], including dogs [3], the E 2 -secreting cells are the Sertoli cells and/or the Leydig cells [13,20]. In men [6,19] abnormally increased testicular E 2 production causes spermatogenic dysfunction, and long-term E 2 administration has been shown to inhibit spermatogenesis in dogs [8,15]. Aromatase inhibitor (AI) blocks the aromatization of androgen to E 2 by inhibiting aromatase enzyme activity [1,18], and AI has been reported to be effective in treating spermatogenic dysfunction in men with high plasma E 2 levels [4].…”

“…Peripheral blood samples were collected from the two azoospermic dogs at the same time as the semen collections. Plasma E 2 and T levels were measured by the radioimmunoassay described previously [8]. The plasma E 2 levels of the two dogs (21 and 22 pg/ml, respectively) were higher than those of two normal Beagles (Dog A and Dog B, as controls)(8.1 and 12.3 pg/ml, respectively), aged 2 and 4 years, and their plasma T levels (1.2 and 1.4 ng/ml) were lower ( Table 2).…”