Supporting information and resources

Salivary Chromogranin A

Salivary Chromogranin A
Chromogranin A (CgA, also known as parathyroid secretory protein 1) is an acidic secretory protein belonging to the granin family, found in many types of neuroendocrine tissues.  It is stored in secretory vesicles with other types of neurotransmitters and peptide hormones.  Granins play an important role in the sorting and aggregation of secretory products in the trans-golgi network, and in the subsequent formation of secretory granules. (1,2,3,4,5)  CgA is co-secreted from sympathetic nerves along with the catecholamines, and it has been shown to be useful as a biomarker of sympathetic nervous activity. CgA production has been found in human submandibular saliva glands, and CgA can be measured in saliva. The correlation between saliva and serum CgA is not well understood. (5,6,7) A circadian rhythm for CgA in normal subjects has been reported, with peak values during the night around 11:00 and a nadir in the morning around 8:00. (8)