Effects of Primary Sex Hormones and Hormone Receptors on the Vocal Mechanism

Project Summary/Abstract Sex hormones are critical to vocal fold (VF) health; however, the individual effects of sex hormones and their hormone receptors on the VFs are poorly understood.

This gap in knowledge is perpetuated by both the general inaccessibility of the VFs as well as the complex relationship between hormones and the voice that is muddied in the human voice literature by confounding factors.

Thus, better understanding how hormones affect the underlying laryngeal mechanism and consequently vocal functions is critical to preventing and treating hormone-related voice disorders.

Therefore, primary objectives of this research are to first quantify sex hormone receptors in the VFs (Aim 1) and then quantify changes to VF biology (Aim 2a) and vocal acoustics (Aim 2b) for each primary sex hormone (testosterone, estradiol, and progesterone) and their corresponding hormone receptors.

Using a rat model, we will test the central hypotheses that the distribution of receptors in the VFs will be different in male vs. female rats (Aim 1).

In gonadectomized rats, selectively activating hormone receptors for testosterone (male), estradiol (female), and progesterone (female) will show changes in structure and function in the VF mucosa and thyroarytenoid muscles (Aim 2a) and will lead to changes in vocal acoustics (Aim 2b).

By defining individual hormone contributions to VF health and vocal behavior, this research will provide scientific direction for the prevention and reversal of hormone-related voice disorders.

This work is innovative due to the specialized methodology that will 1) quantify hormone receptors in the VFs and 2) selectively activate specific hormone receptors to differentiate individual contributions of primary sex hormones and their hormone receptors on VF biology and acoustic behavior.

This work is significant because knowledge of hormone-specific effects on vocal acoustics is critical to understanding which therapeutic strategies may reverse vocal function changes attributable to the loss of sex hormones.

This training program will provide the time, tools, environment, and mentorship necessary for the PI to become an independent translational voice researcher.

Training activities will capitalize on 1) using the specialized resources and equipment and 2) learning from the uniquely-qualified mentors available at the University of Wisconsin-Madison.

These experiences will provide the PI with tailored training that will build on their previous research that evaluated how hormones affect intrinsic laryngeal muscles and acoustics, maximize their methodological skillset, expand their theoretical framework of voice disorders, refine their scientific writing and dissemination, and scaffold their ability to continue a fundable, durable, programmatic line of research that will contribute to the discipline of communication sciences and disorders.

This translational line of voice research is important to advance the discipline of speech-language pathology by disambiguating the effects of hormones and their receptors on the vocal mechanism allowing for more informed evaluation, treatment, and prevention of voice disorders.