GHRH-stimulated pituitary small extracellular vesicles inhibit hepatocyte proliferation and IGF-1 expression by its cargo miR-375-3p.

Small extracellular vesicles (sEV) have emerged as a novel mode of intercellular material transport and information transmission. It has been suggested hormones may regulate the production and function of sEV. However, the specific impact of growth hormone-releasing hormone (GHRH) on pituitary sEV production and the role of sEV in the regulation of the GHRH-GH-IGF axis has not been previously reported. The results of the present study demonstrated that GHRH increased the production of pituitary sEV by promoting the expression of Rab27a. More importantly, GHRH induced alterations in protein and miRNA levels within GH3-sEV components. Notably, GH3-sEV with GHRH treatment exhibited the enhanced ability to impede BRL 3A cell proliferation and the expression of IGF-1. Conclusively, for the first time, we corroborate the influence of GHRH on pituitary sEV, thereby presenting novel evidence for how sEV participates in the balance of the GHRH-GH-IGF axis. Importantly, this study provides new insight into a novel balance mechanism mediated by sEV within the endocrine system.