Gender differences in brown adipose tissue-related brain functional networks: an 18F-FDG-PET study

Thermogenesis of brown adipose tissue (BAT) is controlled by central modulating mechanisms, although changes in brain metabolism of BAT-positive subjects with different genders are still unclear. We hypothesized that changes in regional cerebral glucose metabolic activity were associated with BAT activities, and this association differed in different genders.

Brain glucose metabolism of 26 BAT-positive and 26 BAT-negative healthy subjects was compared using a brain fluorodeoxyglucose (FDG)-PET scan, and gender differences in BAT-related brain functional networks and effect of sex hormones were assessed by comparing the brain PET images of BAT-positive and BAT-negative subjects of different genders and postmenopausal female subjects.

Compared with controls, BAT-positive male subjects had a significant hypermetabolic area in the right extranuclear and significant hypometabolic areas in the right inferior parietal lobule and right inferior frontal gyrus; while at the same threshold, BAT-positive female subjects had richer hypermetabolic regions, including bilateral limbic lobes, bilateral frontal lobes, right cerebellum, left sublobar, and right parietal lobe. However, BAT-positive postmenopause female subjects only showed significant hypometabolic regions in left lingual gyrus.

BAT-related brain functional networks are different between male and female subjects. Female networks are more significant and more concentrated while male networks are smaller and more dispersed, and these gender differences may be related to sex hormones.