Secretin
Secretin was the first hormone to be identified. 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 (chyme) through the pyloric sphincter 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.
Discovery and development of antiandrogens
Flutamide became the first NSAA to be tested clinically. Later the NSAAs bicalutamide and nilutamide were developed. The alleged advantages of these compounds were that they did not affect libido or potency like the other centrally acting compounds under development, luteinizing-hormone-releasing hormone (LHRH) agonists and cyproterone acetate. But this theory did not prove to be true. These NSAAs eventually crossed the blood–brain barrier, like cyproterone acetate, leading to a subsequent increase in serum testosterone levels.