SCT

SCT Full Name

secretin

SCT Introduction

Secretin is a classic gastrointestinal peptide hormone that plays an important role in the neuroendocrine regulation of digestion. It is the first substance identified as a hormone, establishing the concept of chemical messengers spreading through the bloodstream to affect distant organs. Mainly produced by S cells in the mucosa of the small intestine, duodenum, and jejunum, its main function is to regulate the pH value of duodenal contents by stimulating the secretion of bicarbonate rich fluids from the pancreas and liver.

Figure.Mechanism of secretin. (Source:Zhou T, et al, 2018)

Synthesis and Release
Production location: Secretin are synthesized and stored in specialized intestinal endocrine S cells located in the Lieberk ü hn crypts of the duodenum and upper jejunum.
Release trigger factor: The main physiological stimulus for the release of secreted hormones is the decrease in pH value (increase in acidity) in the duodenal cavity. This usually occurs when gastric chyme (a mixture of partially digested food and acidic gastric juice) enters the small intestine.
Mechanism: Brightness acidity (pH<4.5) directly stimulates S cells through specific chemical sensors. Other factors, such as bile salts and fatty acids, can also promote their release, although acidity is the main triggering factor.

Central Nervous System Function
Secretin and their receptors are expressed in discrete brain regions such as the paraventricular nucleus (PVN) and arcuate nucleus (Arc) of the hypothalamus, which are crucial for energy homeostasis and neurological function. It regulates appetite by activating the melanocortin system: central or peripheral administration of secretin upregulates the expression of prefrontal melanocortin (POMC) in Arc, downregulates the expression of agouti related protein (AgRP), and increases the expression of melanocortin-4 receptor (MC4R) in PVN. In addition, secretin is essential for maintaining hippocampal synaptic function and neural progenitor cells, indicating its potential role in cognitive function and neuroprotection.

Alternate Names for SCT

SCT; secretin; prepro-secretin;

• 1. Zhou T, Wu N, Meng F, Venter J, Giang TK, Francis H, Kyritsi K, Wu C, Franchitto A, Alvaro D, Marzioni M. Knockout of secretin receptor reduces biliary damage and liver fibrosis in Mdr2-/- mice by diminishing senescence of cholangiocytes. Laboratory investigation. 2018, 98(11):1449-64.