Ultrasound Imaging of the Testes and Accessory Sex Glands in Buffalo Bulls Treated with Gonadotrophic Releasing Hormone (original) (raw)
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Reproduction, 2003
Administration of GnRH agonist for an extended period inhibits pulsatile LH release but enhances testicular function of bulls. The mechanism whereby long-term administration of GnRH agonist enhances testosterone concentration in the blood of bulls has not been determined. The aim of this study was to determine whether chronic treatment with the GnRH agonist, azagly-nafarelin, increases blood concentrations of LH and FSH in prepubertal bulls. Two different doses of the GnRH agonist were administered via Alzet mini-osmotic pumps for 28 days. Blood samples were collected at 20 min intervals for 24 h at days 2, 13 and 25 of treatment. Agonist-treated groups had reduced testosterone pulse frequency (P < 0.05) and increased mean and basal concentrations of testosterone (P < 0.05) compared with untreated control bulls. Basal LH concentrations were higher in agonist-treated bulls during all three periods (P < 0.05) and overall (1 ng ml −1 higher, compared with control bulls; P < 0.001). Frequency of LH pulses in the agonist-treated groups was reduced to less than one pulse in 24 h. Agonist-treated bulls tended to have (P < 0.10) or had (P < 0.05) a slight but significant increase in blood FSH concentration. In conclusion, the higher blood testosterone concentration in bulls after prolonged treatment with GnRH agonist may result, at least in part, from changes in the testes induced by enhanced basal concentration of LH.
The Journal of veterinary medical science / the Japanese Society of Veterinary Science, 2015
Although color Doppler ultrasonography has been used to evaluate testicular blood flow in many species, very little has been done in goat. Eight male Shiba goats were exposed to a single intramuscular injection of either gonadotropin-releasing hormone (GnRH group; 1 µg/kg BW) or human chorionic gonadotropin (hCG group; 25 IU/kg BW). Plasma testosterone (T), estradiol (E2), and inhibin (INH) were measured just before (0 hr), and at different intervals post injection by radioimmunoassay. Testis volume (TV) and Doppler indices such as resistive index (RI) and pulsatility index (PI) of the supratesticular artery were measured by B-mode and color Doppler ultrasonography, respectively. The results indicated an increase in testicular blood flow in both groups, as RI and PI decreased significantly (P<0.05), but this increase was significant higher and earlier in hCG group (1 hr) than in the GnRH group (2 hr). A high correlation was found for RI and PI with both T (RI, r= -0.862; PI, r= -...
Journal of Animal Science, 2005
The objective was to compare testis characteristics of Zebu bulls treated with the GnRH agonist, deslorelin, at different times and for different durations during their development. An additional objective was to determine the usefulness of a stain for the transcription factor GATA-binding protein 4 (GATA-4) as a specific marker for Sertoli cell nuclei in cattle. Bulls (54) were allocated to nine groups (n = 6) and received s.c. deslorelin implants as follows: G1 = from birth to 3 mo of age; G2 = from 3 to 6 mo; G3 = from 6 to 9 mo; G4 = from 9 to 12 mo; G5 = from birth to 15 mo; G6 = from 3 to 15 mo; G7 = from 6 to 15 mo; G8 = from 12 to 15 mo; and G9 (control) = no implant. Bulls were castrated at 19 mo of age. Paraffin sections (10 m) were subjected to quantitative morphometry and GATA-4 immunohistochemistry. At castration, all bulls in the control group (6/6) had attained puberty (scrotal circumference ≥ 28 cm), whereas a smaller proportion (P < 0.05) had reached puberty in G2 (2/5) and G6 (1/ 6). Bulls in G2 and G6 also had a lesser (P < 0.05) testis
EFFECT OF GnRH ANALOGUE ON LIBIDO AND SEMEN CHARACTERISTICS OF PUBERAL BUFFALO BULLS
Egyptian puberal buffalo bulls (n=9); aged 15-18 months; allocated into three groups (n= 3/group) to verify the effect of different doses (8 μg, 12 μg or 16 μg) of GnRH analogue (Buserelin acetate) on the sexual desire and semen characteristics. Bulls treated with 12 μg of Buserelin were superior to those injected with 8 µg or 16 µg where it shortened the reaction time (6.51±0.38min. vs. 7.48±0.41min. and 7.46±0.40min., respectively) and improved the semen quantity: increased the ejaculate volume (2.22± 0.13ml vs. 1.89± 0.13 ml and 1.54±0.11ml, respectively) and sperm cell concentration (957±86.60×106 sperm/ml vs. 928±86.76×106 sperm/ml and 779±53.62×10 6 sperm/ml, respectively), improved the sperm motility (57.13±1.36% vs. 63.29±1.55% and 56.11±1.51%, respectively) and sperm livability (66.80± 1.23% vs. 69.12± 1.45% and 67.85± 1.87%, respectively), and lower sperm abnormalities (5.08±0.33% vs. 11.30± 0.95% and 9.16±0.49%, respectively). Instead, Buserelin injection increased testosterone levels in a dose-dependent-manner (1.73±0.57ng/ml, 4.61±1.28ng/ml and 4.79±1.21 ng/ml in 8 μg, 12 μg and 16 μg groups, respectively).These results demonstrated that GnRH injection at a dose of 12 μg is optimal to maximize the libido and semen quality of pubertal buffalo bulls. KEY WORDS: Buffalo bulls, GnRH, Semen, Testosterone ( (B BV VM MJ J--S SE E [ [1 1] ]: : 2 28 8--3 34 4; ; 2 20 01 11 1) ) P BENHA UNIVERSITY FACULTY OF VETERINARY MEDICINE B BE EN NH HA A V VE ET TE ER RI IN NA AR RY Y M ME ED DI IC CA AL L J JO OU UR RN NA AL L B BE EN NH HA A V VE ET TE ER RI IN NA AR RY Y M ME ED DI IC CA AL L J JO OU UR RN NA AL L ( (2 20 01 11 1) )--S SP PE EC CI IA AL L
SVU-International Journal of Veterinary Sciences, 2021
The vascularization of the testis through testicular artery is of great importance to maintain its normal function. The vascular disruption due to inadequate arterial blood flow of the testis negatively affects testicular function and semen quality. This study aimed to determine the efficacy of gonadotropin-releasing hormone (GnRH) administration on testicular vascularity in relation to testosterone hormonal response. Five clinically healthy adult ossimi rams 18-to 30-months-old were used. Testicular arteries Doppler examination, blood sampling following GnRH administration and testosterone hormonal assay were conducted. Both pulsatility index (PI) and resistance index (RI) significantly decreased in all treated rams starting from 1 hr till 120 hrs after single GnRH administration, both Doppler indices returned to their pre-treatment values at 144 hours after GnRH administration. Doppler peak systolic velocity (PSV) did not change in response to GnRH administration. Testosterone hormone concentrations negatively correlated with PI and RI but not PSV. In conclusion, GnRH would be useful a beneficial therapy for the treatment of testicular dysfunction in rams by increasing testosterone concentrations and testicular blood flow. And pulse wave Doppler ultrasonography would be a useful non-invasive clinical tool for evaluation of the efficacy of novel therapeutic treatments in rams.
Reproduction, 1997
In bull calves serum concentrations of LH, FSH, and to a lesser extent testosterone, are increased transiently, between 6 and 20 weeks of age. The function of gonadotrophin and testosterone secretion in this period of growth and development was tested by injecting five Hereford bull calves with a GnRH agonist (15 mg Leuprolide acetate) i.m. at 6, 10 and 14 weeks of age; five vehicle treated calves acted as controls. On the basis of blood samples taken every 15 min for 10 h, at 12 weeks of age, mean serum concentrations of LH, FSH and testosterone and LH and FSH pulse frequency and amplitude were decreased (P < 0.05) by Leuprolide acetate. At 24 weeks of age, mean serum concentrations of LH, and LH and FSH pulse frequency in Leuprolide acetate treated calves exceeded (P < 0.05) that seen in control calves. On the basis of blood samples taken every other week, treatment with Leuprolide acetate decreased mean serum concentrations of FSH and testosterone at 14, 16 and 18 weeks of age compared with control calves and delayed the peak of the early increase in LH secretion from 20 to 24 weeks of age (P < 0.05). Scrotal circumference between 22 and 50 weeks of age, pixel units from ultrasound images of the testes, testis mass at castration at 50 weeks of age, and numbers of spermatids and pachytene spermatocytes were all lower in Leuprolide treated calves than in controls. A transient increase in secretion of LH, FSH and testosterone in young bull calves before 20 weeks of age may, therefore, be a critical step in the initiation and timing of testicular development in bull calves.
The present study aims to investigate the Luteinizing hormone (LH), testosterone and total estrogens response to exogenous gonadotropin-releasing hormone (GnRH) in adult crossbred bulls with differing semen quality. Fourteen adult crossbred bulls of differing semen quality were selected and treated with 10 mg of GnRH (Buserelin acetate) intramuscularly. Blood samples of the bulls were collected at an interval of 30 min commencing 1 h prior to GnRH treatment until 4 h post-GnRH treatment and thereafter, at an interval of 1 h for the next 3 h. The endocrine response in terms of peak values, area under the curve, and the time taken to attain peak values for LH, testosterone, and total estrogens were evaluated in all the bulls. The mean 7 SEM peak levels of LH, testosterone, and total estrogens were found to be 150 7 24.1, 5.3 7 0.69, and 0.077 0.01 ng/mL, respectively. The mean 7 SEM area under the curve of LH, testosterone, and total estrogens were found to be 392 7 51.3, 23.57 3.4, and 0.32 7 0.04 ng/mL Â h, respectively. The relationships between hormonal responses (LH, testosterone, and total estrogens) and semen quality were analyzed using the linear regression method, which provided nonsignificant (P 40.05) results. This study indicated that the gonadal and pituitary hormonal response to single exogenous GnRH treatment may have no relationship with the semen quality of crossbred bulls.
Journal of Reproduction and Development, 2011
The present study investigated the basal levels and GnRH-induced responses of peripheral testosterone and estrogen in Holstein bulls with poor semen quality. On the basis of semen parameters, bulls (n=5) having poor semen quality were selected as experimental bulls, and good semen quality bulls (n=4) were used as control bulls. Both groups were treated intramuscularly once with GnRH (250 μg of fertirelin acetate). Blood samples were collected at-1 day (d),-30 min and 0 h (treatment) followed by every 30 min for 5 h and 1, 3 and 5 d post-GnRH treatment (PGT), and LH, testosterone and estradiol-17β (E2) concentrations were measured. The pretreatment concentrations were used as basal levels. The percentage increments based on the 0-h levels were calculated per bull for each sampling time until 5 h PGT, and differences were compared between the experimental and control groups. The PGT concentrations of testosterone and basal and PGT concentrations of E2 were significantly lower in the experimental group. The testosterone increment in the experimental group was delayed and significantly lower from 1 to 5 h PGT than those in the control group. It can be suggested that bulls with poor semen quality have delayed and lower GnRH-induced testosterone response and may also have lower estrogen levels.
Theriogenology, 1994
Thirty crossbred bulls, 12 to 13 mo of age, were used to examine the relationship of testosterone and progesterone concentrations and testosterone:progesterone ratio to measurements of testicular function. Bulls were allotted to 1 of 2 groups based on scrotal circumferences (SC) as follows: the Small SC (n=20) group had scrotal circumference less than 28 cm while the Large SC (n=10) group had scrotal circumference greater than 28 cm. All bulls were administered GnRH (100 ug, ira), and blood was obtained immediately prior to injection (t=0), 30 min after injection (t=30) and 2 to 3 h after injection (t=150). Serum was assayed for concentrations of testosterone and progesterone. Semen was evaluated for the percentage of morphologically normal spermatozoa. Testicular parenchyma was sectioned and stained, and 300 cross sections per testis of seminiferous tubules were examined under a light microscope and classified as either active (spermatocytes and spermatids present) or inactive (no spermatocytes or spermatids present). Although progesterone concentrations varied widely (range: 21 pg/ml to 1070 pg/ml), repeated measurements from individual bulls were highly correlated (r"=0.74) and did not change significantly (P > 0.1) in response to GnRH treatment. Small SC bulls had a higher percentage of inactive seminiferous tubules (P < 0.001) and a lower percentage. morphologically normal spermatozoa (P < 0.001) than Large SC bulls, but no differences in testosterone or progesterone concentrations or in the ratio of testosterone:progesterone were detected. Mean serum testosterone concentration increased (P < 0.0001) by 30 min after GnRH treatment and continued to increase (P < 0.0001) through t=150 but did not differ (p > 0.1) between groups. Normal testosterone secretion in response to GnRH injection suggested that no biochemical lesions in the testosterone production pathway were present in bulls with very small scrotal circumference.