激素的合成与释放 mRNA Signal sequence Ribosome Golgi apparatus Messenger RNA on the ribosomes of the ER binds amino acids into a Preprohormone peptide chain called a preprohormone. The chain is directed into the ER lumen by a signal sequence of amino acids. Prohormone Endoplasmic 2Enzymes in the ER chop off the signal reticulum(ER) sequence,creating an inactive prohormone. The prohormone passes from the ER through the Golgi apparatus. Active hormone Peptide Secretory vesicles containing enzymes Prohormone fragment and prohormone bud off the Golgi.The enzymes chop the prohormone into one Release Secretory or more active peptides plus additional vesicle signal peptide fragments. The secretory vesicle releases its contents by exocytosis into the y extracellular space. Extracellular space Blood 6 The hormone moves into the circulation 6 vessel for transport to its target.● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 激素的合成与释放