HN Equine Research Challenge: Can Synthetic Hormones Suppress the Horse’s Immune System?

Can exogenous hormones, such as Depo, suppress the immune system in horses, leading to a predisposition to infection? Carleigh Fedorka seeks to answer this question: learn more about her research here, and how you can support her project!

We’re proudly introducing the projects participating in our first-ever equine research crowdfunding challenge with Experiment.com! To learn more about why we sponsored this crowdfunding challenge, click here.

Many horse owners use hormones in their equine partners — approximately 33% of mares will be given hormone therapy at least once in their lives. We administer hormones for all kinds of reasons. The predictable ones are to aid in conception and breeding and as therapy for hormonal dysfunction. More recently, people have also started to use hormones as behavioral modification.

But no good treatment comes without side effects. In humans and mice, exogenous hormones can suppress the immune system, leading to a predisposition to infection. In horses? We just don’t know yet.

Carleigh Fedorka, who you may know from her fantastic work with the racing industry, is trying to find out the answer to just this question. This summer she is studying how two well-known synthetic hormones — Altrenogest (aka Regumate) and medroxyprogesterone acetate (aka MPA or Depo-Provera) — interact with equine cells in the lab. She’ll measure how these hormones influence the cells’ abilities to produce infection-fighting molecules, and whether the progesterone-like drugs actually attack those cells.

Hear it from Carleigh herself!

If synthetic hormones do suppress a horse’s immune system, it will require us to reconsider the risks we take with horses who are on those hormones. Travel, which we already know stresses the equine immune system, and exposure to new horses both become riskier with a suppressed immune system. And owners might want to consider high-exposure environments like shows carefully.

But right now, this is all still a big question! Carleigh needs to raise around $4500 to conduct this study over the Summer. You can support her work over on her Experiment campaign, and follow along with her progress as she runs this study!

The bottom line

• Pilot research suggests that Altrenogest is associated with immune suppression in mares
• We still need more data to know how synthetic hormones affect immune function in other horses
• You can support Carleigh’s research by contributing to her crowdfunding campaign!