[Biosynthesis and secretory regulation of pituitary prolactin]

We summarized recent advancements in biosynthesis and secretory regulation of pituitary prolactin at the cellular and molecular levels from some literatures. We singled out dopamine, estrogen and thyrotropin releasing hormone (TRH) from many factors controlling the biosynthesis and the regulation, because they are important, physiologically and pathologically. Dopamine exerts some effects on the membranes of the lactotrope inhibiting activities of cAMP, phosphatidylinositols and calcium ion channels. It inhibits prolactin gene transcription by suppressing action of the promoter region. Estrogen and TRH increase prolactin biosynthesis and the secretory regulation. Estrogen coupled with the receptors in the cytoplasma goes directly to the DNA region -1713-->-1495 being upstream to the starting site of prolactin transcription and differing from the region on which dopamine acts. TRH accelerates prolactin production and release in such steps as transcription, stabilization of mRNA, accumulation of mRNA in the cytoplasma, protein synthesis and exocytosis.