Testicular blood flow and plasma concentrations of testosterone and total estrogen in the stallion after the administration of human chorionic gonadotropin.
Abstract: The goal of this study was to investigate for the first time a possible association between plasma concentrations of testosterone and total estrogen and testicular blood flow in the stallion. Correlations between these variables were calculated before and after administration of human chorionic gonadotropin (hCG). Eight mature warmblood stallions received 5,000 IU hCG intravenously, and four stallions received solvent only. Testicular blood flow in the left and right testicular arteries was assessed using colour Doppler sonography by measuring blood flow volume (BFV) and pulsatility index (PI) immediately before (time 0) and 1, 3, 6, 12, 24, 72, 120 and 168 h after hCG administration. EDTA blood samples were collected after each examination from a jugular vein to measure plasma testosterone and total estrogen concentrations. After treatment, the BFV increased and was elevated at 1 h and between 12 and 24 h. The profile of the PI was contrary to that of the BFV throughout the study period. Following hCG, there was a biphasic increase in testosterone concentration with maxima between 1 and 3 h and between 24 and 72 h, and there was a monophasic increase in the total estrogen concentration with a maximum between 6 and 24 h. At time 0, the total estrogen concentration correlated significantly with BFV (r=0.90; P0.05). The testosterone and total estrogen concentrations did not correlate with PI (P>0.05). The total estrogen concentration, but not testosterone, correlated well with BFV after injection of hCG (P<0.05). The results of this study indicated that the testicular blood flow volume of the stallion may be regulated by estrogens, but additional studies are necessary to investigate whether there is a causal relationship.
Publication Date: 2008-07-30 PubMed ID: 18667792DOI: 10.1262/jrd.20014Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Controlled Clinical Trial
- Journal Article
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research article explores the correlation between testosterone, total estrogen levels, and testicular blood flow in stallions before and after hCG administration. This study may offer insights into how male hormones regulation within the equine species.
Methodology
- The study took a sample of eight mature warmblood stallions and four stallions (as a controlled group) that were administered with a solvent only.
- The eight stallions received an intravenous injection of 5,000 IU human chorionic gonadotropin (hCG).
- Color Doppler sonography was used to monitor the blood flow volume (BFV) as well as the pulsatility index (PI) of both testicular arteries in each stallion over prescribed intervals.
- The intervals used were immediately before the administration of the hCG (time 0), then 1, 3, 6, 12, 24, 72, 120, and 168 hours afterwards.
- EDTA blood samples were collected from a jugular vein after each Doppler examination in order to measure testosterone and total estrogen concentrations in the plasma.
Results
- An increase in testicular BFV was observed at 1 hour and between 12-24 hours after hCG administration.
- The PI, on the contrary, presented a profile which was the exact opposite of BFV during the entire study period.
- An initial rise in testosterone level occurred between 1 to 3 hours which secondarily peaked between 24 to 72 hours after hCG administration, showing a biphasic response.
- Estrogen levels rose in a monophasic pattern with a peak concentration observed between 6 to 24 hours following hCG administration.
- Prior to hCG injection, a significant correlation existed between total estrogen concentration and BFV but not with testosterone concentration.
- Neither hormone concentration correlated with the PI.
- The post-hCG total estrogen concentration, but not the testosterone level, demonstrated a significant correlation with the BFV.
Conclusion
- The observed increase in testicular blood flow following hCG administration, coupled with the significant correlation between total estrogen concentration and BFV, suggests that estrogens may play a role in regulating testicular blood flow in stallions. However, lack of correlation with testosterone does not rule out its potential role completely.
- Conclusively, the study proposed a correlation between estrogen concentration and testicular blood flow, however, a causal relationship is yet to be studied further.
Cite This Article
APA
Bollwein H, Schulze JJ, Miyamoto A, Sieme H.
(2008).
Testicular blood flow and plasma concentrations of testosterone and total estrogen in the stallion after the administration of human chorionic gonadotropin.
J Reprod Dev, 54(5), 335-339.
https://doi.org/10.1262/jrd.20014 Publication
Researcher Affiliations
- Clinics for Cattle, University of Veterinary Medicine, Hanover, Germany. Heinrich.Bollwein@tiho-hannover.de
MeSH Terms
- Animals
- Chorionic Gonadotropin / administration & dosage
- Chorionic Gonadotropin / pharmacology
- Estrogens / blood
- Horses / blood
- Horses / physiology
- Injections, Intravenous
- Male
- Regional Blood Flow / drug effects
- Testis / blood supply
- Testis / diagnostic imaging
- Testis / drug effects
- Testosterone / blood
- Time Factors
- Ultrasonography, Doppler, Color / veterinary
Citations
This article has been cited 23 times.- Samir H, El-Sherbiny HR, Ahmed AE, Ahmad Sindi R, Al Syaad KM, Abdelnaby EA. Administration of Estradiol Benzoate Enhances Ovarian and Uterine Hemodynamics in Postpartum Dairy Buffaloes. Animals (Basel) 2023 Jul 18;13(14).
- Samir H, Mandour AS, Radwan F, Swelum AA, Nagaoka K, Sasaki K, Watanabe G. Effect of xylazine sedation on testicular blood flow, testicular echotexture, and circulating hormones in Shiba goats. Vet Res Commun 2023 Jun;47(2):849-859.
- Samir H, ElSayed MI, Radwan F, Hedia M, Hendawy H, Hendawy AO, Elbadawy M, Watanabe G. An updated insight on testicular hemodynamics: Environmental, physiological, and technical perspectives in farm and companion animals. Vet Res Commun 2023 Jun;47(2):323-345.
- Ortega-Ferrusola C, Gómez-Arrones V, Martín-Cano FE, Gil MC, Peña FJ, Gaitskell-Phillips G, Da Silva-Álvarez E. Advances in the ultrasound diagnosis in equine reproductive medicine: New approaches. Reprod Domest Anim 2022 Oct;57 Suppl 5(Suppl 5):34-44.
- El-Sherbiny HR, El-Shalofy AS, Samir H. Exogenous L-carnitine Administration Ameliorates the Adverse Effects of Heat Stress on Testicular Hemodynamics, Echotexture, and Total Antioxidant Capacity in Rams. Front Vet Sci 2022;9:860771.
- El Zawam A, Tibary A, Patino C. Basal Levels and hCG Responses of Serum Testosterone and Estrogen in Male Alpacas. Front Vet Sci 2020;7:595856.
- Ademola OJ, Alimba CG, Bakare AA. Reproductive toxicity assessment of Olusosun municipal landfill leachate in Mus musculus using abnormal sperm morphology and dominant lethal mutation assays. Environ Anal Health Toxicol 2020 Jun;35(2):e2020010.
- Toishi Y, Tsunoda N, Nagata SI, Kirisawa R, Nagaoka K, Watanabe G, Yanagawa Y, Katagiri S, Taya K. Evaluation of the chemiluminescent enzyme immunoassay system for the measurement of testosterone in the serum and whole blood of stallions. J Reprod Dev 2018 Feb 27;64(1):41-47.
- Ortiz-Rodriguez JM, Anel-Lopez L, Martín-Muñoz P, Álvarez M, Gaitskell-Phillips G, Anel L, Rodríguez-Medina P, Peña FJ, Ortega Ferrusola C. Pulse Doppler ultrasound as a tool for the diagnosis of chronic testicular dysfunction in stallions. PLoS One 2017;12(5):e0175878.
- Samir H, Sasaki K, Ahmed E, Karen A, Nagaoka K, El Sayed M, Taya K, Watanabe G. Effect of a single injection of gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) on testicular blood flow measured by color doppler ultrasonography in male Shiba goats. J Vet Med Sci 2015 May;77(5):549-56.
- Hattori N, Gopal AK, Shields AT, Fisher DR, Gooley T, Pagel JM, Press OW, Rajendran JG. 131I-tositumomab myeloablative radioimmunotherapy for non-Hodgkin's lymphoma: radiation dose to the testes. Nucl Med Commun 2012 Dec;33(12):1225-31.
- Kutzler M, Tyson R, Grimes M, Timm K. Determination of testicular blood flow in camelids using vascular casting and color pulsed-wave Doppler ultrasonography. Vet Med Int 2011;2011:638602.
- Abdelnaby EA. The impacts of L-citrulline and sildenafil on penile and testicular vascular perfusion pattern, advanced testicular analysis, steroids, and semen picture in normospermic dogs. Vet Res Commun 2025 Nov 19;50(1):45.
- Abdelnaby EA, Ghoneim IM, Marzok M, Fathi M, El-Sherbiny HR, Emam IA. Seasonal variations in testicular imaging, hemodynamic patterns, semen quality, hormonal, nitric oxide levels, and antioxidant profiles in male camel (Camelus dromedaries). Vet Res Commun 2025 Oct 29;50(1):5.
- Karmoty AFE, Fathi M, Emam IA, Tolba A, Abdelnaby EA, Alhaider AK, Abouelela YS. Alterations in the penile artery blood flow hemodynamics and hormonal profile in jacks (Equus asinus) after a single administration of human chorionic gonadotropin (hCG). BMC Vet Res 2025 Oct 3;21(1):572.
- Abdelnaby EA, El-Sherbiny HR, Alhaider AK, Marzok M, Emam IA. Effect of Immunization Against Inhibin on Camel Testicular Morphometry, Echotexture Analysis, Semen Quality, and Vascularization in Relation to Hormonal Aspect. Vet Sci 2025 Sep 15;12(9).
- Abdelnaby EA, Alhaider AK, Emam IA. Effect of repeated injection of human chorionic gonadotropin on semen quality, testicular hemodynamics and hormonal profile of senile camel. Vet Res Commun 2025 Sep 5;49(5):301.
- Fayez E, Salama A, Ismail MA, Youssef FS, Rawash ZM, Oshba MR, Samir H. Dietary supplementation of Astragalus polysaccharide or its nanoparticles enhances testicular hemodynamics, echotexture, scrotal circumference, concentration of testosterone, estradiol, nitric oxide, and total antioxidant capacity, and semen quality in mature Ossimi rams. BMC Vet Res 2025 Feb 6;21(1):55.
- Essam M, ElSayed MAI, Youssef FS, Samir H. Effect of administration of nanoparticles of human chorionic gonadotropin on testicular hemodynamics, testicular volume, testicular echotexture, and circulating testosterone and nitric oxide in pubescent goat bucks under heat stress conditions. Vet Res Commun 2025 Jan 15;49(2):78.
- Samir H, Elfadadny A, Radwan F, Swelum AA, Watanabe G. Alterations in the uterine echotexture, hemodynamics, and histological findings in relation to metabolomic profiles in goats with different ovarian activities (active versus inactive ovaries). Vet Res Commun 2025 Jan 10;49(2):70.
- Fayez E, Samir H, Youssef FS, Salama A, ElSayed MA. Administration of melatonin nanoparticles improves testicular blood flow, echotexture of testicular parenchyma, scrotal circumference, and levels of estradiol and nitric oxide in prepubertal ossimi rams under summer heat stress. Vet Res Commun 2024 Dec;48(6):3953-3965.
- Budiyanto A, Hartanto S, Widayanti R, Kurnianto H, Wardi W, Haryanto B, Munir IM, Ibrahim A, Ludfiani DD. Impact of melatonin administration on sperm quality, steroid hormone levels, and testicular blood flow parameters in small ruminants: A meta-analysis. Vet World 2024 Apr;17(4):911-921.
- Samir H, Mandour AS, Radwan F, Ahmed AE, Momenah MA, Aldawood NA, Yoshida T, Watanabe G, El-Sherbiny HR. Effect of Acute Melatonin Injection on Metabolomic and Testicular Artery Hemodynamic Changes and Circulating Hormones in Shiba Goats under Sub-Tropical Environmental Conditions. Animals (Basel) 2023 May 29;13(11).
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
