Testosterone and Neurovascular Control in Humans
- Registration Number
- NCT04819204
- Lead Sponsor
- Western University, Canada
- Brief Summary
The purpose of these studies are to evaluate the role of testosterone on autonomic and vascular function in men.
- Detailed Description
Sex hormones play a pivotal role in neurovascular function in humans. In recent years, great strides have been made in elucidating the roles of estrogen and progesterone on autonomic and vascular control in women; however, very little is known about the impact of testosterone in men. Given that low testosterone levels are associated with an increased risk of cardiovascular disease, reduced exercise capacity and vascular dysfunction, it is evident that testosterone plays a pivotal role in autonomic and vascular function in men. Our current understanding of testosterone's effects on neurovascular control are confounded by numerous factors that independently alter autonomic and vascular function such as aging and chronic disease (e.g. cardiovascular disease, metabolic disease). The purpose of these studies are to evaluate the role of testosterone on autonomic and vascular function in young men to better isolate the effects of testosterone from the aforementioned confounding factors. The outcomes of these studies will provide novel information regarding the role of male sex hormones in autonomic and vascular control, and further our understanding of the influence of sex hormones on human physiology.
Recruitment & Eligibility
- Status
- UNKNOWN
- Sex
- Male
- Target Recruitment
- 20
- Moderately active
- Free of chronic disease
- congenital or acquired hypogonadism
- drug/alcohol dependence
- hypertension
- current smoker
- current opioid or cannabis user
- diabetes
- inability to provide written consent
- parkinson's disease
- cardiovascular disease
- testosterone use within the last year
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description GnRH antagonist + Testosterone add-back Testosterone gel Intervention: Cetrorelix acetate (Cetrotide) + Testosterone gel (Androgel) GnRH antagonist alone Cetrorelix Acetate Intervention: Cetrorelix acetate (Cetrotide) GnRH antagonist + Testosterone add-back Cetrorelix Acetate Intervention: Cetrorelix acetate (Cetrotide) + Testosterone gel (Androgel)
- Primary Outcome Measures
Name Time Method Muscle sympathetic nerve activity After 7 days GnRH antagonist alone and 7 days GnRH antagonist + Testosterone Multi-unit postganglionic muscle sympathetic nerve activity (MSNA) will be measured by inserting a unipolar tungsten microelectrode into the peroneal nerve near the fibular head of the leg. Neural signals will be amplified, filtered (bandwidth, 700-2,000 Hz), rectified, and integrated (time constant, 0.1 s) to obtain mean voltage neurograms. MSNA will be measured during both trials to evaluate the effect of testosterone on sympathetic activity directed toward the musculature.
Endothelial function After 7 days GnRH antagonist alone and 7 days GnRH antagonist + Testosterone Brachial artery flow-mediated dilation (FMD). Brachial artery FMD measures will be performed non-invasively via Doppler ultrasound.
Forearm blood flow After 7 days GnRH antagonist alone and 7 days GnRH antagonist + Testosterone Forearm blood flow will be measured using Doppler ultrasound at baseline and during stress (e.g. exercise)
- Secondary Outcome Measures
Name Time Method Skeletal muscle microvascular blood flow After 7 days GnRH antagonist alone and 7 days GnRH antagonist + Testosterone Microvascular blood flow will be measured using Diffuse correlation spectroscopy.
Trial Locations
- Locations (1)
the University of Western Ontario
🇨🇦London, Ontario, Canada