SFU alumnus Ashley Monks is changing the way we think of sex hormones by examining their role in neurological and muscular development from a biopsychological perspective.

Sex hormones, the most commonly known being testosterone and estradiol, are already known to play a role in our pubescent development and sexual arousal.

However, the link between sex hormones and nervous and muscular system development have never been fully developed. Monks is trying to change that.

His lab at the University of Toronto primarily use their days to research sexual differentiation and the link between sex hormones and development.

In an SFU media release, Monks explained, “My research seeks to understand how sex hormones shape the nervous system and how the brain is organized, and ultimately to uncover the biological basis behind what makes men and women different and how that actually works.”

Monks’ previous research has shown that sex hormones can rewire the adult brain and its motor neurons responsible for sending messages around the body. It was previously believed that protein molecules called cadherins, which facilitate cell adhesion and binding of tissues, were only active in the early developmental stages of human growth.

However, Monks’ lab successfully established that sex hormones can trigger and regulate cadherin activity throughout our entire life. This led Monks to the conclusion that sex hormones, through cadherin activity, directly affect neural development, even in fully matured adults.

“My research seeks to uncover the biological basis behind what makes men and women different.”

Ashley Monks, SFU alumnus

Monks looked at the muscular development of Arctic ground squirrels, who undergo rapid and uninterrupted muscle growth in preparation for the winter hibernation season. Such rapid growth would cause a number of negative side effects if it were to occur in the human body.

Monks and other researchers found that in the summer Arctic ground squirrels have 10 to 200 times the normally observed levels of androgens (testosterone and other male sex hormones) than other squirrels. The squirrels also had four times the androgen muscular receptors, allowing the muscles to detect the hormones and increase their growth.

However, the ground squirrels have fewer hormone receptors than normal in their lymph nodes, and the lymph nodes are unable to detect the increased levels of androgen in the blood stream. This diminishes the negative side effects of increased sex hormones in their bodies.

This research presents a whole new set of side effects of both the medical usage of hormone replacement therapy and the use of steroids to aid muscle development.

Monks’ research reveals that while muscular development is regulated and aided by sex hormones, the use of hormonal therapy can not only lead to negative muscular and sexual growth, but also affect neurological development.

Monks uses his research to find new methods for treating muscular diseases such as muscular atrophy and Kennedy’s disease, both affecting the transmission of nervous signals between the nervous system and the muscular system.

By shedding light on unknown links between sex hormones — previously thought to only aid in sexual development — and the rest of the body, Monks hopes his research will change the way scientists will use and treat sex hormones.