This summer I had the opportunity to do research as a part of the Summer Program for Undergraduate Urology Research program at UW-Madison working with Dr. Chad Vezina and graduate student Marcela Amberogi.
My research interests lie in trans and queer studies, especially focused on trans healthcare and effects of hormone replacement therapy (HRT). These interests have strengthened throughout the course of my academic career as a Women’s Studies and Biology dual degree student, and through my own journey of transition. This summer, I was able to further the collective of knowledge into the effects of testosterone HRT through the study of serotonin. I focused specifically on neuroendocrine cells in the urethra (in humans and mice) that synthesize serotonin. You might be thinking, isn’t serotonin just a neurotransmitter? Actually, 90% of the serotonin in your body lies outside your central nervous system!
Neuroendocrine cells are in three main places in the body—the lungs, gut, and urethra—and are hypothesized to assist in infection protection. Marcela’s prior research suggested that estrogen may play a role in how these cells are able to function. However, no one had investigated the possible effects of testosterone on these cells in the urethra. That’s where I came in.
I inserted testosterone (T) implants under the skin in 6 female adult mice and compared them to 6 control mice one-week post-implant. Although these implants have limitations, and they aren’t a direct replication of human HRT or hormonal intersex conditions, they’re as close as we can get to studying trans and intersex issues in a model organism. No evidence of incontinence was found, but this could be due to the short duration of the implant. We found that the urethras of the T-implanted mice exhibited significantly weaker contraction to serotonin and bacteria than the control mice. A few serotonin receptors that may assist in contraction were also reduced in the urethras of T-treated mice. This means testosterone may reduce urethral neuroendocrine signaling which in turn may trigger adverse outcomes of incontinence and increased susceptibility of UTI among people assigned female at birth (AFAB) who undergo androgen therapy or have hormone-affected intersex conditions. Post-menopausal AFAB people of all gender identities who use topical T may also be affected. However, we don’t know yet whether estrogen or testosterone levels are more important to neuroendocrine cells.
This summer was really satisfying for me, knowing that I was helping my community and contributing to under-researched populations. I am hopeful that in the future evidence-based information about “UTIs and testosterone” or any information about our trans bodies for that matter, will be readily available and won’t be something transmascs have to scour Reddit to learn about.