How Estrone Works on Stifles

What's that you say? You sense uninformed internet bullshit?
When I was first told that estrogen shots can work to alleviate sticky stifle issues in horses, I will admit to being very skeptical. The whole thing sounded kind of crazy. How does the primary female sex hormone stop joint pain? Why have I never heard of it before? Are horse people crazy?

Long story short, yes. Horse people are crazy. Still, I couldn't argue with results. Estrone shots DO work to help alleviate stifle issues in my horse. But, how?

I dove deep into the internet archives to try to find an answer, but that seemed to only confuse the issue further. Some said they believed the hormone loosened the ligaments in the stifle, because high estrogen levels are common during childbirth-- a period in which ligaments are known to stretch in women. Others said that actually it tightened ligaments, for the same reason. Even more others said that it encouraged the building of muscle. The reasons went on an on... but none of them actually made sense.

So I made the crazy decision to ask my vet, a certified medical professional. Amazingly, he gave me a very simple and plausible reason the hormone works on stifles...

Bloating.

No, really. Stick with me here. It turns out, there is a fat pad beneath the ligaments involved in locking the stifle. When a horse is given Estrone, the fat pads retain water and bloat up.
Actually, yes. But in my case it's probably more to do with all the salt and beer I just ingested than hormones.
Anyway, these bloated fat pads push the ligaments up a tiny bit, allowing them to more easily slide in and out of the locking position. This gives the horse some relief from pain, so he can work properly to build up muscle support for the joint.
Stifle joint. Photo from Behind the Bit. Fat pads are located above and below the joint, under the ligaments.
So there you go. The easy scientific explanation for how and why estrogen works to alleviate stifle pain. Never say my obsessive research down a horrible rabbit hole of misinformation never lead to profitable information. You're welcome.

Comments

  1. well now. I learned something new. And so early in the morning too!

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    1. Learning early in the day is the best!

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    2. Estrone is one of the three naturally occurring estrogens, the others being estradiol and estriol. Estrone is synthesized from androstenedione by the aromatase enzyme system in the ovaries and placenta, and is also synthesized from estradiol by 17-hydroxy steroid dehydrogenase in the liver. Estrone

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  2. I wonder the same thing and hadn't had time to read. Thanks for this. I love knowing why things work.

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  3. That is fascinating! Science is so cool.

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  4. I never knew this is how that worked! Go science!

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  5. That's so interesting! Does it affect the rest of him too (lol I can just imagine every fat pad bloating)? Or is it a localized injection? Either way, glad it's helping! Hopefully Pig will be feeling better soon :)

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    1. I usually give it in the neck, though you can also give it in the acupuncture points for the stifle. Those seem harder to find, though. It does seem to affect the rest of him. He looks a little fluffier after I give them. But, so I do every once in awhile. I won't judge. ;)

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  6. Bodies... the ultimate weird gross machine

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  7. This is cool knowledge. How does the estrogen effect mares though? I have a mare with a bad stifle, but she's already very parish.

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    1. Oooh. I dunno. Good question! I'd imagine that the small amount doesn't effect them much...

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  8. Interesting. I had heard of people using some type of estrogen injection years ago at the track to loosen ligaments (can't remember the official name). I was curious how that would actually work, so thanks for posting.

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  9. What the heck! Interesting though :)

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