Secretin

Stimulus

Secretin is secreted in response to low duodenal pH due to chyme, which contains hydrochloric acid, entering from the stomach. It is the active form of prosecretin.

Function

Secretin stimulates the secretion of pancreas.

It counteracts blood glucose concentration spikes by triggering increased glucose intake.^[1]

It also reduces acid secretion from the stomach by inhibiting enzymes from the pancreas (eg, pancreatic amylase and pancreatic lipase) function optimally at neutral pH.

Structure

Secretin is a glucagon.

History

In 1902, William Bayliss and Ernest Starling were studying how the nervous system controls the process of digestion. It was known that the pancreas secreted digestive juices in response to the passage of food into the duodenum. They discovered (by cutting all the nerves to the pancreas in their experimental animals) that this process was not, in fact, governed by the nervous system. They determined that a substance secreted by the intestinal lining stimulates the pancreas after being transported via the bloodstream. They named this intestinal secretion secretin. Secretin was the first such "chemical messenger" identified. This type of substance is now called a hormone, a term coined by Bayliss in 1905.

References

1. ^ Kraegen EW, Chisholm DJ, Young JD, Lazarus L (1970). "The gastrointestinal stimulus to insulin release. II. A dual action of secretin". J. Clin. Invest. 49 (3): 524-9. PMID 5415678. Free Full Text

See also

• Secretin receptor