Sexual behavior, seminal pH and accessory sex gland weights in geldings administered testosterone and(or) estradiol-17 beta.
Abstract: Sixteen stallions were castrated and 30 days later assigned to one of four treatments: (1) testosterone propionate (175 microgram/kg body weight), (2) 17 beta-estradiol-3-benzoate (44 micrograms/kg body weight), (3) a combination of both steroids or, (4) vehicle only. These dosage were administered every other day for 18 days. The dosages were then doubled and continued for 20 days. Concentrations of testosterone and estradiol in serum decreased rapidly after castration and stabilized within about 6 hours. Mean concentrations of testosterone and estradiol maintained by the steroids were 1.4 and 90 pg/ml, respectively, during treatment at the lower dosage, and 2.6 and 186 pg/ml during treatment at the higher dosage. Libido and the ability to ejaculate were gradually lost after castration. Testosterone restored both aspects of sexual behavior within 2 weeks. Estradiol effectively restored libido at the higher dosage, but was less effective in restoring the ability to ejaculate. The pH of gel-free semen increased after castration and was subsequently decreased by treatment with testosterone or the combination of both steroids. Estradiol had no effect on seminal pH. Weights of the seminal vesicles, ampullae and prostate were greater in geldings treated with testosterone or with both steroids than in estradiol-treated or control geldings. Since estradiol alone was able to restore libido in geldings, it is possible that the maintenance of libido in intact stallions involves either estradiol secreted directly by the testes or estradiol arising from aromatization in peripheral tissues. Treatment with estradiol at either concentration, did not appear to affect the size or function of sex glands in geldings.
Publication Date: 1980-12-01 PubMed ID: 7204276DOI: 10.2527/jas1981.5161358xGoogle Scholar: Lookup
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- Journal Article
Summary
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The study explored how administering testosterone and/or estradiol-17 beta affected sexual behavior, seminal pH, and the weight of accessory sex glands in castrated stallions. It found that testosterone restored libido and ejaculation, while estradiol only restored libido. Testosterone or a combination of both hormones lowered seminal pH levels and increased the weight of seminal vesicles, ampullae, and prostate.
Methodology
- Sixteen stallions participated in this research. They were castrated and allowed to heal for 30 days before commencing with the study.
- The stallions were then split into four groups. Each group followed a different treatment plan. The first group was given testosterone propionate, the second was administered 17 beta-estradiol-3-benzoate, the third got a combination of both steroids, and the fourth group served as a control and did not receive any steroids.
- All dosages were delivered every other day over 18 days, then the dosages were doubled and the experiment continued for another 20 days.
Findings
- The concentration of testosterone and estradiol in the blood decreased quickly following castration but became stable in about 6 hours.
- Libido and the ability to ejaculate reduced gradually after castration. Within two weeks of testosterone treatment, these traits were restored.
- Higher doses of estradiol also restored libido, but was less successful in restoring the ability to ejaculate.
- The pH value of semen increased after castration but was reduced by administering testosterone, or a combination of testosterone and estradiol. Estradiol alone had no effect on seminal pH levels.
- The weights of the seminal vesicles, ampullae, and prostate were greater in those treated with testosterone, or both hormones, compared to those treated with estradiol or the control group.
Conclusion
- The research suggests that estradiol might be involved in maintaining libido in intact stallions. This could result from estradiol secreted directly by the testes or from peripheral tissue aromatization.
- The experimental treatment with estradiol at either concentration did not seem to influence the size or function of the geldings’ sex glands.
Cite This Article
APA
Thompson DL, Pickett BW, Squires EL, Nett TM.
(1980).
Sexual behavior, seminal pH and accessory sex gland weights in geldings administered testosterone and(or) estradiol-17 beta.
J Anim Sci, 51(6), 1358-1366.
https://doi.org/10.2527/jas1981.5161358x Publication
Researcher Affiliations
MeSH Terms
- Animals
- Castration / veterinary
- Estradiol / pharmacology
- Horses / physiology
- Hydrogen-Ion Concentration
- Libido / drug effects
- Male
- Organ Size / drug effects
- Semen / drug effects
- Sexual Behavior, Animal / drug effects
- Testosterone / pharmacology
Citations
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