Secretin, Cholecystokinin and Newer Gastrointestinal Hormones

IN 1902, Bayliss and Starling1 demonstrated that the introduction of hydrochloric acid into a denervated loop of small intestine elicited the brisk secretion of pancreatic juice. The implications of this observation were appreciated immediately, and they suggested that some unidentified, blood-borne "chemical messenger" was released from the acidified intestine to mediate this response. According to Babkin,2 the word "hormone" was introduced by Starling on the suggestion of Mr. W.B. Hardy.3 The word is from the Greek, ο͑ρμαω, meaning "I arouse to activity" or "I excite."Although the study of endocrinology may have begun, in one sense, in 1902 with the . . .