The 'Hormone Secretin' was the first hormone to be discovered. It was discovered by: MCQ with Answer and Explanation

Secretin was the first hormone ever to be identified, marking the birth of endocrinology as a distinct field. It was discovered in 1902 by British physiologists William Bayliss and Ernest Starling. They observed that when acidic chyme entered the duodenum, it stimulated the pancreas to secrete bicarbonate-rich juice, even if all nerves to the pancreas were cut. They concluded that a chemical messenger (which Starling coined the term 'hormone' for in 1905) was released from the intestinal mucosa into the blood to stimulate the pancreas. They named this messenger secretin.