UBC Reports | Vol. 48 | No. 5 | Mar.
7, 2002
Connection may explain some disorders’ gender balance
by Hilary Thomson staff writer
If the sex hormone testosterone is powerful enough to produce
puberty changes such as hair growth and sex drive, how does it affect
the body the rest of the time?
Victor Viau, an assistant professor of Anatomy, is exploring the
role of sex hormones and how they affect our response to stress.
He aims to find where in the brain the interface between sex hormones,
stress and depression occurs.
“We know that sex steroids and their receptors show up everywhere
in the body including the brain, but we don’t know their role,”
says the Montreal native, who came to UBC in 2000 from the University
of California at San Francisco.
“We also know that there are gender differences in stress-related
illnesses and variations in hormonal levels associated with those
illnesses. I hope to better understand the interaction between these
various systems.”
He wants to reveal the pathways, transmitters and cellular mechanisms
that testosterone uses to alter the brain circuits that relay stress-related
information. His work may help to diagnose and treat depression
and other sex dependent disorders including cardiovascular and metabolic
diseases.
Viau’s focus is the hypothalamic-pituitary-adrenal (HPA) axis,
an important hormonal system that controls the secretion of the
steroid cortisol from the adrenal gland.
Cortisol protects us from the effects of acute stress by regulating
processes such as blood pressure and immune function. When the body
is subjected to chronic stress, however, the steroid is implicated
in causing disease such as depression.
Testosterone acts on the HPA axis to inhibit the release
of the stress steroid cortisol, which may explain why males react
differently to stress than females.
Viau notes that many men with depression show reduced testosterone
levels, suggesting that naturally occurring variations in testosterone
levels may have a bearing on the cause of depression.
Case studies show that where the patient is not responding to anti-depressant
medication an alteration in testosterone levels may lead to improvement.
Also, the incidence of suicide among pubescent males may be connected
with both cortisol and testosterone levels. “Stress listens to what
is going on in the reproductive system — there is functional cross
talk between sex steroids and the adrenal system,” he says.
The connection to sex hormones may help to explain why some disorders
linked to stress are seen more commonly in one sex than the other.
Depression is more commonly found in women; schizophrenia and cardiovascular
disease in men.
Although the research questions are simple, they must be attacked
in a multi-disciplinary way, says Viau, who draws on expertise from
the fields of neuroscience, psychology and endocrinology.
