sekretiinin

Sekretin is a hormone produced primarily by the S cells (also known as Senter cells) in the duodenum, the first segment of the small intestine. It plays a crucial role in regulating digestion by stimulating the pancreas to release bicarbonate-rich pancreatic juice, which neutralizes stomach acid entering the duodenum from the stomach. This neutralization is essential for protecting the intestinal lining from acid damage and creating an optimal environment for enzymatic digestion.

Discovered in 1902 by William Maddock Bayliss and Ernest Henry Starling, sekretin was the first hormone to be identified and named. The term "hormone" itself was coined by Starling to describe substances like sekretin that are secreted into the bloodstream to exert effects on distant organs. Bayliss and Starling conducted experiments where they observed that infusing acid into the duodenum triggered pancreatic secretion, leading to the isolation and characterization of sekretin.

Sekretin also influences gallbladder contraction and bile flow by stimulating the release of bile from the liver and gallbladder, further aiding digestion. Its secretion is stimulated by the presence of acidic chyme entering the duodenum and inhibited by alkaline conditions. While sekretin’s primary function is digestive, its discovery laid the foundation for modern endocrinology, the study of hormone function.

Abnormal sekretin levels or dysfunction may contribute to digestive disorders, though research in this area remains limited. Synthetic sekretin analogs have been explored in medical research, particularly for diagnostic imaging of the pancreas, such as in secretin-stimulated magnetic resonance cholangiopancreatography (MRCP). However, its clinical use remains largely experimental.