The role of lysosomes and proteases in hormone secretion and degradation.

In endocrine cells, complex relationships exist between the lysosome and hormone secretion. These relationships may have developed from a common evolutionary origin. As lysosomal and secretory systems evolved, diverse functional relationships developed between them. From a basic intracellular “digestive” role, lysosomes and their proteolytic enzymes developed new and varied origins and functions in hormone processing, release, and intraand extracellular degradation. 1.1 Proteolytic enzymes and hormone availability Hormone effects are a function of the availability of hormone at target receptors. Proteolytic enzymes can have an important role in regulating the availability of hormone by: 1) increasing the intracellular production of secreted forms from precursors, 2) facilitating release or exocytosis, 3) decreasing intracellular concentrations by degradation of excessive intracellular hormone, 4) inactivation or activation of hormone by proteolytic enzymes in serum, and 5) degradation of hormone in target...