thyrotropin-releasing hormone 5-oxo-prolyl-histidyl-prolinamide A tripeptide hormone that originates in the HYPOTHALAMUS and stimulates the secretion of THYROTROPIN from the PITUITARY GLAND. In humans, it also acts as a prolactin-releasing factor. It is also a neurotransmitter in the central nervous system. MeSH:D013973 TRH protirelin thyroliberin pituitary hormone-releasing hormone