Sex steroid hormones and brain function: PET imaging as a tool for research

Area of Science:

• Neuroendocrinology
• Neuroimaging
• Molecular Psychiatry

Background:

• Sex steroid hormones regulate sexual characteristics and are produced in the brain, influencing neural function, behavior, and higher cognitive processes.
• Aberrant steroid hormone signaling is linked to psychiatric disorders like anxiety and depression, while neurosteroids may offer neuroprotection in neurodegenerative diseases.
• Current research predominantly relies on post-mortem tissue analysis, limiting longitudinal studies of dynamic steroid hormone interactions in the brain.

Purpose of the Study:

• To review the current applications and potential of Positron Emission Tomography (PET) imaging in studying sex steroid hormones within the brain.
• To highlight PET's role in investigating the dynamic interplay between sex steroids, their receptors, brain function, and behavior in both physiological and pathological conditions.
• To assess PET's utility in bridging findings from animal studies to human clinical trials for neurological and psychiatric disorders.

Main Methods:

• Discussion of Positron Emission Tomography (PET) as a non-invasive in vivo imaging technique utilizing radiotracers.
• Review of PET's application in quantifying sex hormone receptor expression and key steroid synthesis enzymes (e.g., aromatase) in the brain.
• Evaluation of PET's capacity to assess the effects of hormonal treatments by imaging downstream neural processes.

Main Results:

• PET imaging has been explored for measuring sex hormone receptor expression and aromatase activity in the brain.
• PET can visualize the impact of hormonal interventions on specific brain functions.
• While some validated radiotracers are still needed, PET demonstrates significant utility in current steroid hormone research.

Conclusions:

• PET imaging represents a valuable non-invasive tool for studying sex steroid hormones and their receptors in the brain.
• This technique facilitates longitudinal research into the role of steroid hormones in psychiatric and neurological disorders.
• PET imaging holds promise for translating preclinical findings into clinical applications for human brain disorders.