Brain is an endocrine organ through secretion and nuclear transfer of parathymosin.

This study reports that parathymosin (PTMS) is secreted by hypothalamic stem/progenitor cells (htNSC) to inhibit senescence of recipient cells such as fibroblasts. Upon release, PTMS is rapidly transferred into the nuclei of various cell types, including neuronal GT1-7 cells and different peripheral cells, and it is effectively transferred into neuronal nuclei in various brain regions in vivo. Notably, brain neurons also produce and release PTMS, and because neuronal populations are large, they are important for maintaining PTMS in the cerebrospinal fluid which is further transferable into the blood. Compared with several other brain regions, the hypothalamus is stronger for long-distance PTMS transfer, supporting a key hypothalamic role in this function. In physiology, aging is associated with declines in PTMS production and transfer in the brain, and knockdown in the hypothalamus versus hippocampus were studied showing different contributions to neurobehavioral physiology. In conclusion, the brain is an endocrine organ through secretion and nuclear transfer of PTMS, and the hypothalamus-brain orchestration of this function is protective in physiology and counteractive against aging-related disorders.