Instruct: Given a question, retrieve relevant passages that answer the question.
Query: What was the first hormone discovered?
Secretin was the first hormone to be identified.[8] In 1902, William Bayliss and Ernest Starling were studying how the nervous system controls the process of digestion.[9] 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.[10]
In May 2005 Eastern Health discovered errors in hormone receptor breast cancer test results from a histology lab in St Johns, Newfoundland. The tests were designed to register patients' hormone levels, and determine whether they could benefit from potentially life-saving hormone oncology treatments. The board commissioned the re-testing of results from up to 1,500 patients and alerted the office of premier Danny Williams of this development and of potential ensuing media interest. An hour after first contacting Williams's office, the board sent a second message with what communications director Karen Matthews described to the inquiry as a "stand-down" notice, saying the issue had been minimized; Matthews responded by withdrawing the office from high alert over the case. Former health minister John Ottenheimer told the inquiry that he wished to publicize the testing failures when they emerged in May 2005, but deferred to Eastern Health's request that he leave them to handle the affair internally.
In the hypothalamic–adenohypophyseal axis, releasing hormones, also known as hypophysiotropic or hypothalamic hormones, are released from the median eminence, a prolongation of the hypothalamus, into the hypophyseal portal system, which carries them to the anterior pituitary where they exert their regulatory functions on the secretion of adenohypophyseal hormones.
These hypophysiotropic hormones are stimulated by parvocellular neurosecretory cells located in the periventricular area of the hypothalamus. After their release into the capillaries of the third ventricle, the hypophysiotropic hormones travel through what is known as the hypothalamo-pituitary portal circulation. Once they reach their destination in the anterior pituitary, these hormones bind to specific receptors located on the surface of pituitary cells. Depending on which cells are activated through this binding, the pituitary will either begin secreting or stop secreting hormones into the rest of the bloodstream.
For his thesis he studied the wingbeat frequency of Drosophilia, using a stroboscopic device which he designed with the advice of Harold Edgerton. Next he studied the endocrine control of the development of the giant American silkworm "Hyalophora cecropia", introducing carbon dioxide as a surgical anesthetic. He showed that a hormone from the brain activated the prothoracic glands to release the moulting hormone ecdysone. When the juvenile hormone is also present larvae moult to another larval stage. Juvenile hormone is not present during the larval to pupal or the pupal to adult moults. The pupae enter diapause which is broken when the brain has been chilled for weeks, after which it releases the brain hormone. Williams was the first to isolate juvenile hormone and ecdysone. With his students he studied the profound metabolic shutdown during diapause, cocoon spinning behavior, and was the first to discover and isolate cocoonase and cytochrome b5, as well as the "paper factor". He subsequently proposed that hormonal analogues could be used as pesticides by disrupting the developmental cycles of insects.
Carnegie Institution scientists at Cold Spring Harbor made many contributions to genetics and medicine. In 1908 George H. Shull discovered hybrid corn and the genetic principle behind it called heterosis, or "hybrid vigor." This would become the foundation of modern agricultural genetics. Clarence C. Little in 1916 was among the first scientists to demonstrate a genetic component of cancer. E. Carleton MacDowell in 1928 discovered a strain of mouse called C58 that developed spontaneous leukemia – an early mouse model of cancer. In 1933, Oscar Riddle isolated prolactin, the milk secretion hormone and Wilbur Swingle participated in the discovery of adrenocortical hormone, used to treat Addison's disease.
GnIH was discovered in 2000. It is an RFamide peptide that significantly reduced luteinizing hormone release in Coturnix Japonica (Japanese quail). This peptide emerged as the first tropic hormone known to inhibit gonadotropin secretion in the hypothalamic-pituitary-gonadal axis of vertebrates. Subsequent research identified GnIH peptide homologs in variety of mammals, including humans.
Ghrelin was discovered after the ghrelin receptor (called growth hormone secretagogue type 1A receptor or GHS-R) was discovered in 1996 and was reported in 1999. The hormone name is based on its role as a "growth hormone-releasing peptide", with reference to the Proto-Indo-European root "gʰre-", meaning "to grow".
Hormonal IUDs were developed in the 1970s following the development of the copper IUD in the 1960s and 1970s. Dr. Antonio Scommenga, working at the Michael Reese Hospital in Chicago, discovered that administering progesterone inside the uterus could have contraceptive benefits. With knowledge of Scommegna's work, a Finnish doctor, Jouni Valtteri Tapani Luukkainen, created the 'T'-shaped IUD that released progesterone, marketed as the Progestasert System in 1976. This IUD had a short, 1-year lifespan and never achieved widespread popularity. Following this relative lack of success, Dr. Luukkainen replaced the progesterone with the hormone levonorgestrel to be released over a five-year period, creating what is now Mirena.
For simplicity, let’s say that the doctor first receives the blood test (in formulas abbreviated as “BT”) result for the parathyroid hormone analysis, and that it showed a parathyroid hormone level that is elevated relatively to what would be expected by the calcium level.
The catecholamines comprise the endogenous substances dopamine, noradrenaline (norepinephrine) and adrenaline (epinephrine) as well as numerous artificially synthesized compounds such as isoprenaline. Their investigation constitutes a prominent chapter in the history of physiology, biochemistry and pharmacology. Adrenaline was the first hormone extracted from its endocrine gland and obtained in pure form, before the word "hormone" was coined. It was also the first hormone the structure and biosynthesis of which were clarified. Apart from acetylcholine, adrenaline and noradrenaline were the first neurotransmitters to be discovered and the first intercellular biochemical signals to be found in intracellular vesicles. The β-adrenoceptor was the first G protein-coupled receptor the gene of which was cloned.
In particular, he studied metamorphosis. His most significant contribution was the discovery that neurosecretory cells in the brain of the South American kissing bug, "Rhodnius prolixus", secrete a crucial hormone that triggers the prothoracic gland to release prothoracicotropic hormone (PTTH), which regulates the process of metamorphosis. This was the first experimental confirmation of the function of neurosecretory cells. He went on to discover another hormone, called the juvenile hormone, which prevented the development of adult characteristics in "R. prolixus" until the insect had reached the appropriate larval stage. Wigglesworth was able to distort the developmental phases of the insect by controlling levels of this hormone. From these observations, Wigglesworth was able to develop a coherent theory of how an insect's genome can selectively activate hormones which determine its development and morphology.
Prothoracicotropic hormone (PTTH) was the first insect hormone to be discovered. It was originally described simply as "brain hormone" by early workers such as Stefan Kopeć (1922) and Vincent Wigglesworth (1934), who realized that ligation of the head of immature insects could prevent molting or pupation of the body region excluded from the head if the ligation was performed before a critical age in the lifestage was reached. After a certain point the ligation had no effect and both sections of the insect would molt or pupate. However, implantation of a conspecific brain to a sessile ligated abdomen or an abdomen under diapause would induce molting or pupation. Thus, the brain was originally thought to be the source of the hormone that induces molting in insects.
The Gastrin family is a group of peptides evolutionarily similar in structure and function. Commonly synthesized in antroduodenal G-cells. Regulate gastric function along with gastric acid secretion and mucosal growth.The Secretin family are peptides that act as local hormones which regulate regulate activity of G-protein coupled receptors. Most often found in the pancreas and the intestines. Secretin was discovered in 1902 by E. H. Starling. It was later linked to chemical regulation and was the first substance to be deemed a hormone.
3. Mark H. Whitnall, William G. Haynes, David J. Webb (1997). Principles of Medical Biology.
Insects play a large role in what is known about neurosecretion. In simpler organisms neurosecretion mechanisms regulate the heart, the process of metamorphosis, and directly influences the development of the gonadal function. In more advanced organisms the gonadal function is manipulated by the intermediary endocrine processes. Axons from neurosecretory cells trace to corpora cardiaca and corpora allata and produce and secrete a brain hormone which insect physiologists suspect is bound to a large carrier protein. Although the function is unknown, there are a multitude of these cells found in the ventral ganglia of the nerve cord. Neurosecretory cells, found in clusters in the medial and lateral parts of the brain, control corpora allata activity by producing juvenile hormone during the larval or nymphal instars, the phase between periods of molting in insects. The production of this hormone inhibits the insect during the conversion to maturity and reactivating once the fully-grown adult is prepared for reproduction. The 3rd International Symposium on Neurosecretion at the University of Bristol discussed the intracellular structure of the neurosecretory cells and the migration path to the target organs or vascular fluid areas by neurosecretory granules. More is being discovered on the identification of granules in hormones and the linking of their development with the organism’s physiologic state.
Adipokinetic hormone (AKH) is a short peptide hormone that has been studied in insects. It is a lipid mobilising hormone and is responsible for regulating fuel transport in the haemolymph, for redirecting energy to other processes as required by the insect. AKH was initially discovered in the locusts "Locusta migratoria" and "Schistocerca gregaria" and is generally associated with aiding flight. Early observations of locusts showed that despite the fact that lipids are metabolised by flight muscle in order to maintain flight, which would be transported from the haemolymph, there was often still a high concentration of lipids in the haemolymph, implying that an agent may be responsible for activating lipid transport into the haemolymph and this was thought most likely to be hormonal regulation. The hormone itself is part of a larger family, often referred to as red pigment concentrating hormones (RPCH) discovered in crustaceans and the typical makeup of hormones in this family includes a length between 8 and 10 amino acids, blocked N and C termini, phenylalanine or tyrosine at position 4 and tryptophan at position 8. RPCH was discovered in crustaceans and shown to be involved in concentrating red pigments, for sexual displays and a variety of other reasons. The similarity between AKH and RPCH is so significant that injecting insects with RPCH induces an AKH like response and "vice versa" 
Knobil is also credited with discovering the key role of pulsatile Gonadotropin-releasing hormone and estrogen feedback during the menstrual cycle. This work today forms the basis of reproductive endocrinology and enabled development of the world's first hormonal contraceptives.
Estrone was the first steroid hormone to be discovered. It was discovered in 1929 independently by the American scientists Edward Doisy and Edgar Allen and the German biochemist Adolf Butenandt, although Doisy and Allen isolated it two months before Butenandt. They isolated and purified estrone in crystalline form from the urine of pregnant women. Doisy and Allen named it "theelin", while Butenandt named it "progynon" and subsequently referred to it as "folliculin" in his second publication on the substance. Butenandt was later awarded the Nobel Prize in 1939 for the isolation of estrone and his work on sex hormones in general. The molecular formula of estrone was known by 1931, and its chemical structure had been determined by Butenandt by 1932. Following the elucidation of its structure, estrone was additionally referred to as "ketohydroxyestrin" or "oxohydroxyestrin", and the name "estrone", on the basis of its C17 ketone group, was formally established in 1932 at the first meeting of the International Conference on the Standardization of Sex Hormones in London.
Trisporic acid was discovered in 1964 as a metabolite that caused enhanced carotene production in Blakeslea trispora. It was later shown to be the hormone that brought about zygophore production in Mucor mucedo. The American mycologist and geneticist Albert Francis Blakeslee, discovered that some species of Mucorales were self-sterile (heterothallic), in which interactions of two strains, designated (+) and (-), being necessary for the initiation of sexual activity. This interaction was found by Hans Burgeff of the University of Goettingen to be due to the exchange of low molecular weight substances that diffused through the substratum and atmosphere. This work constituted the first demonstration of sex hormone activity in any fungus. The elucidation of the hormonal control of sexual interaction in the Mucorales extends over 60 years and involved mycologists and biochemists from Germany, Italy, the Netherlands, UK and the USA.
Sterling was one of the first researchers to use radioactive iodine to treat thyroid diseases. He used radioisotopic labels to study the metabolism of human serum proteins and red blood cells. He discovered that the body converts the pro-hormone thyroxine into triiodothyronine, the primary active form of thyroid hormone. This breakthrough led to a new field of thyroid hormone research and led to the first early studies on the mechanism of action of thyroid hormones. Sterling developed the equilibrium dialysis method for measuring free thyroxine, which remains the gold standard for evaluating free hormone levels in blood today. Sterling was a pioneering investigator identifying mitochondrial thyroid hormone receptors, shortened isoforms of the full-length, nuclear receptors. He wrote a chapter on thyroid hormone receptors in the fifth edition of "Werner's The Thyroid: A Fundamental and Clinical Text", which is known as "the bible of modern thyroidology."
DHT was first synthesized by Adolf Butenandt and his colleagues in 1935. It was prepared via hydrogenation of testosterone, which had been discovered earlier that year. DHT was introduced for medical use as an AAS in 1953, and was noted to be more potent than testosterone but with reduced androgenicity. It was not elucidated to be an endogenous substance until 1956, when it was shown to be formed from testosterone in rat liver homogenates. In addition, the biological importance of DHT was not realized until the early 1960s, when it was found to be produced by 5α-reductase from circulating testosterone in target tissues like the prostate gland and seminal vesicles and was found to be more potent than testosterone in bioassays. The biological functions of DHT in humans became much more clearly defined upon the discovery and characterization of 5α-reductase type II deficiency in 1974. DHT was the last major sex hormone, the others being testosterone, estradiol, and progesterone, to be discovered, and is unique in that it is the only major sex hormone that functions principally as an intracrine and paracrine hormone rather than as an endocrine hormone.
The first of these factors to be identified are thyrotropin-releasing hormone (TRH) and gonadotropin-releasing hormone (GnRH). TRH is a small peptide that stimulates the secretion of thyroid-stimulating hormone; GnRH (also called luteinizing hormone-releasing hormone) stimulates the secretion of luteinizing hormone and follicle-stimulating hormone.
There are many signals that control catabolism. Most of the known signals are hormones and the molecules involved in metabolism itself. Endocrinologists have traditionally classified many of the hormones as anabolic or catabolic, depending on which part of metabolism they stimulate. The so-called classic catabolic hormones known since the early 20th century are cortisol, glucagon, and adrenaline (and other catecholamines). In recent decades, many more hormones with at least some catabolic effects have been discovered, including cytokines, orexin (also known as hypocretin), and melatonin.
Through his research in endocrinology with colleague Arthur Squires, Farquharson discovered what became known as the "Farquharson Phenomenon": that the introduction of continuous exogenous hormone doses suppresses the natural production of that hormone in the patient and causes temporary atrophy in the producing organ. This phenomenon became one of the basic principles of endocrinology and a key factor in the etiology of hormonal abnormalities. Farquharson also made significant contributions related to anemia and pigment metabolism. He was the first Canadian doctor to publicize Sheehan's syndrome, and the first North American to report on Simmond's disease. As an educator and researcher, he was an early promoter of laboratory testing in the evaluation of illness; he was known for advocating both this and awareness of potential psychological issues in patients.
At the Salk Institute, Vale led efforts in identifying the group of hormones involved in human growth, reproduction and temperature. His group discovered, isolated and identified corticotropin-releasing hormone (CRF/CRH) in 1981 and growth hormone releasing factor (GHRF) in 1982.
Non-tropic hormones are hormones that directly stimulate target cells to induce effects. This differs from the tropic hormones, which act on another endocrine gland.
Non-tropic hormones are those that act directly on targeted tissues or cells, and not on other endocrine gland to stimulate release of other hormones. Many hormones act in a chain reaction. Tropic hormones usually act in the beginning of the reaction stimulating other endocrine gland to eventually release non-tropic hormones. These are the ones that act in the end of the chain reaction on other cells that are not part of other endocrine gland. 
The Hypothalamic-pituitary-adrenal axis is a perfect example of this chain reaction. The reaction begins in the hypothalamus with a release of corticotropin-releasing hormone/factor (CRH/F; tropic). This stimulates the anterior pituitary and causes it to release Adrenocorticotropic hormone (ACTH; tropic) to the adrenal glands. Lastly, cortisol (non-tropic) is secreted from the adrenal glands and goes into the bloodstream where it can have more widespread effects on organs and tissues. Since cortisol is what finally reaches other tissues in the body, it is a non-tropic hormone. CRH an ACTH are tropic hormones because they act on the anterior pituitary gland and adrenal glands, respectively, both of which are endocrine glands. 
Non-tropic hormones are thus often the last piece of a larger process and chain of hormone secretion. Both tropic and non-tropic hormones are necessary for proper endocrine function. For example, if ACTH (Adrenocorticotropin hormone; a tropic hormone) is inhibited, cortisol can no longer be released because the chain reaction has been interrupted. 
Some examples of non-tropic hormones are: 
Most endocrine glands, such as the gonads, pancreas, and adrenal glands, produce non-tropic hormones. Those released from the pituitary gland in the brain include: