The full article is at the following link.
High-Dose Testosterone Treatment Increases Serotonin Transporter Binding in Transgender PeopleBiological Psychiatry, 2014
Kranz, G.S. and others
http://www.sciencedirect.com/science/article/pii/S0006322314007094AbstractBackground - Women are two times more likely to be diagnosed with depression than men. Sex hormones modulating serotonergic transmission are proposed to partly underlie these epidemiological findings. Here, we used the cross-sex steroid hormone treatment of transsexuals seeking sex reassignment as a model to investigate acute and chronic effects of testosterone and estradiol on serotonin transporter (SERT) binding in female-to-male (FtM) and male-to-female (MtF) transsexuals.
Methods - 33 transsexuals underwent [11C]DASB PET before start of treatment, a subset of which underwent a second scan four weeks, and a third scan four months, after treatment start. SERT BPND was quantified in 12 regions of interest. Treatment effects were analyzed using linear mixed models. Changes of hormone plasma levels were correlated with changes in regional SERT BPND.
Results - One and four months of androgen treatment in FtM increased SERT binding in amygdala, caudate, putamen and median raphe nucleus. SERT binding increases correlated with treatment induced increases in testosterone levels, suggesting that testosterone increases SERT expression on the cell surface. Conversely, four months of anti-androgen and estrogen treatment in MtF led to decreases in SERT binding in insula, anterior and mid-cingulate cortex. Increases in estradiol levels correlated negatively with decreases in regional SERT binding, indicating a protective effect of estradiol against SERT loss.
Conclusions - Given the central role of the SERT in the treatment of depression and anxiety disorders, these findings may lead to new treatment modalities and expand our understanding of the mechanism of action of antidepressant treatment properties.
