Serum level of sex steroid hormone is associated with diversity and profiles of human gut microbiome.

Gut microbiota plays roles in host physiology including endocrine function. Although some data suggest a potential connection between biological sex differences and gut microbiota, the connection between sex steroid hormones and gut microbes remained unexplored. The current study investigates the relationship between gut microbes and serum levels of testosterone in men and estradiol in women. Fecal microbiota from a total of 57 men (n = 31) and women (n = 26) were assessed using 16s rRNA gene sequencing. Based on the levels of serum testosterone and estradiol in men and women, respectively, participants were stratified into three groups of Low, Medium, and High. Microbiome communities were analyzed as a function of the steroid hormone within sex. Men and women in the High group harbored more diverse gut microbial communities than others. In men, the abundance of Acinetobacter, Dorea, Ruminococcus, and Megamonas correlated significantly with testosterone levels. Women in the High group have more Bacteroidetes and less Firmicutes phyla than those in the Low group. Genera Slackia and Butyricimonas were significantly correlated with estradiol levels. These results demonstrate that sex steroid hormone levels are correlated with diversity and gut microbial composition, and provide fundamental information helpful for developing communication networks between human and microbial communities.