Jensen et al. demonstrated that global GH excess and deficiency affected the gut microbiota in mature adult and middle-aged mice.19,20 Moreover, the gut microbiota in patients with GH-secreting pituitary adenoma is significantly altered and strongly associated with GH/IGF-1 axis.21 Therefore, exploring the roles of GH signaling in gut microbiota regulation can provide a better understanding of the pathophysiological process of diseases related to impaired GH axis. This evidence concerns the gene GH1 and pituitary gland adenoma.