Indenopyride derivative RTI-4587-073(l): A candidate for male contraception in stallions

Malgorzata A. Pozor, Margo L. Macpherson, Sue M. McDonnell, Maggie Nollin, Janet F. Roser, Charles Love, Scott Runyon, Brian F. Thomas, Mats H. Troedsson

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The objective of this study was to determine whether an indenopyridine derivative RTI-4587-073(l) was a good candidate for male contraception in horses. We hypothesized that a single administration of RTI-4587-073(l) causes significant suppression of testicular function in stallions without affecting sexual behavior. Three Miniature horse stallions received a single dose of 12.5 mg/kg RTI-4587-073(l) orally (group "treated"), whereas three other Miniature horse stallions received placebo only (group "control"). Semen was collected and evaluated from all stallions twice a week for three baseline weeks and 13 post-treatment weeks. Sexual behavior was video-recorded and analyzed. Testicular dimensions were measured using ultrasonography, and blood samples were drawn for endocrine evaluation once before treatment and once a week during the post-treatment period. Single administration of RTI-4587-073(l) caused severe oligoasthenozoospermia (low sperm number and low motility), shedding large numbers of immature germ cells in semen, and increased FSH concentrations in treated stallions. These effects were fully reversible within ~71 days. However, libido and copulatory behavior remained unchanged throughout the entire experiment. We concluded that RTI-4587-073(l) was a promising candidate for male contraceptive in domestic stallions. Further research should be performed to test this compound for fertility control in wildlife and humans.

Original languageEnglish
Pages (from-to)1006-1016
Number of pages11
Issue number9
StatePublished - Dec 2013

Bibliographical note

Funding Information:
This work was funded by the University of Florida , College of Veterinary Medicine Equine Windfall Endowment. RTI-4587-073(l) was kindly provided by the Research Triangle Institute , Research Triangle Park, NC, USA. Maggie Nollin was funded by a Merial Veterinary Scholars Summer Research Program . Drs Erin Runcan and Mohamadou Diaw assisted with semen collection.


  • FSH
  • Indenopyridine
  • Male contraception
  • Sexual behavior
  • Stallion semen
  • Wildlife

ASJC Scopus subject areas

  • Small Animals
  • Food Animals
  • Animal Science and Zoology
  • Equine


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