ESPE Yearbook of Paediatric Endocrinology

Psychoneuroendocrinology. 2022; 137: 105604. PMID: 34971856https://pubmed.ncbi.nlm.nih.gov/34971856/

Brief Summary: This study evaluated the associations between the amygdala total and sub-region volumes in relation to sex hormones – estradiol and free testosterone – as a function of age and genetic differences in androgen receptor sensitivity in 297 adolescents. It provides new knowledge regarding the influence of sex hormones on amygdala sub-regions.

The amygdala is well-studied in many aspects. However, previous studies on the effect of sex steroid hormones during development and amygdala sub-region volumes show mixed results. These authors investigated the effects of sex hormones (free testosterone and estradiol) on amygdala volumes using magnetic resonance imaging (MRI) in 297 adolescents aged 10-17 years. Androgen receptor (AR) CAG repeat number was assessed as a marker of transcriptional activity and androgen sensitivity.

They did not find any overall relationship between amygdala volumes and sex hormones or AR sensitivity. However, sex-specific differences were observed. Specifically, amygdala volumes in females were more influenced by AR genetic variation, where lower AR sensitivity was associated with larger basolateral complex volumes. In males, the interactions of testosterone, age, and AR polymorphism were more relevant for the amygdala volumes in the basolateral complex and cortico-medial subnuclei. The authors speculate that this may be partially explained by differing expression levels of AR, aromatase expression, or possibly both, between amygdala subregions. This is the first study to investigate whether genetic variation in the AR may independently or jointly interact with hormone concentrations and/or age influencing the amygdala and its subregions volumes in adolescents. While the study provides new knowledge regarding the influence of sex hormones on amygdala subregions, the effects observed are small and need to be confirmed.