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Nice section. I am expanding and making a couple of tweaks. Current medical usage of growth hormone is not "human growth hormone/HGH", but I put an explanatory note in the growth hormone article. I moved the Orexin reference from "see also" (why not all the other hormones) to the list of hormones. alteripse 10 apr 04

is the definition a bit loose or is it just me? as is it would include neurotransmitter and all the autacoids! is that correct? Erich 08:34, 19 May 2004 (UTC)

There is a grey area between hormones and neurotransmitters. Think adrenalin. Think about all those peptide hormones that affect neurotransmission. Also, many are paracrine mediators th-- (talk) 03:04, 15 August 2010 (UTC)at hardly fit in the hormone concept (eicosanoids are degraded before they can exert influence on other organs). This page should probably be phrased rather broadly. Perhaps we could introduce a section that delineates "true hormones" from chemo-, lympho- and cytokines, interleukins, prostanoids and other locally active mediators (although interleukins and cytokines have systemic effects). JFW | T@lk 10:24, 19 May 2004 (UTC)
Gedday JFW, trust me, I know adrenaline. I understand the overlap, but I didn't think that all the neurotransmitters are hormones. The current definition (ie A hormone (from Greek horman - "to set in motion") is a chemical messenger from one cell (or group of cells) to another.) would include ACh and glutamate and every other neurotransmitter and autacoid as hormones. but it's not my area... Erich 11:21, 19 May 2004 (UTC)
Ah, the Gasboy has finally changed his signature back from e.
Of course you know adrenaline... or do you rather use ephedrine when an oldtimer remains bradycardic and hypotensive despite atropine...
I suggest we ask Alter ipse amicus for his opinion. JFW | T@lk 11:39, 19 May 2004 (UTC)

A formal distinction would be whether the neurotransmitters signal any farther than the distance of the synapse, in which case few would classify them as hormones. For research purposes, there are hundreds of chemical signals that are technically hormones. Every organ in the body is an endocrine organ, making hormones (brain, heart, lungs, skin, fat, intestines, etc). You can review the program of the upcoming Endocrine Society meetings and see a wide range of interests [1]. On the other hand, clinical endocrinologists restrict their attentions to the "classic" hormone systems of growth puberty, sex, fuel metabolism, wt regulation, calcium balance, etc. AlteripseAlteripse 23:40, 19 May 2004 (UTC)

so... the current definition is too broad??? Erich 23:24, 19 May 2004 (UTC)

Cytokines and all those things certainly fit any definition of hormone I can think of. However, I would argue that neurotransmitters can be described as a "local" enough signal that few people would call them hormones. Alteripse 23:40, 19 May 2004 (UTC)

yes the hh:mm, dd mmm yyyy tending to drown out 'e' which i'm otherwise fond of... back to 'Erich' for a while. Oddly Jiang's sig has appeal... well pacing sounds like the go in that situation if you've given maximal atropine. I guess you could give some adrenaline as well. vasoconstrictors tend slow the heart, but they are good in anaesthesia because the anaesthetics drop bp mainly by vasodilation. ephedrine is popular, and i've often got an ampule in my pocket. metaraminol is a potent vacoconstritor and does the job but phenylephrine is gaining in popularity. anyway I digress... yes i think alteripse will know all! Erich 12:51, 19 May 2004 (UTC)
If I may add my two cents worth, I'd say that "some compounds released from cells" can be a hormone and a neurotransmitter, or both. I don't think there is much gray area between hormones and neurotransmitters. It's the role played by the compound that is relevant. When it is transmitting signals between neurons, it's a neurotransmitter. When it is carrying out signals from an endocrine gland (which can be any tissues these days) along the bloodstream to it's specific target tissues where the receptor is expressed, it's a hormone. Some compounds, like the catecholamines, are capable of both, but don't expect them to do both jobs at the same time at the same locale.
The gray area, IMHO, lies with cytokines, which usually act locally (autocrine / paracrine) and don't ride with the blood to their targets. I see cytokines as a unique set of hormones with immune- and/or growth-related paracrine actions to multiple target cell types all expressing the receptors ....
PFHLai 13:49, 2004 May 20 (UTC)
There should be a section that discusses how steroid hormones activate prossess in target cells and how they differ from other hormones. C. Nelson

You are right, we have a steroid article but it doesn't treat steroid receptors and how they work in the nucleus to affect DNA transcription. Someday, when I get a round tuit... But anyone is welcome to jump in and do it. alteripse 01:37, 2 Mar 2005 (UTC)

Given that this is an encylopedia, surely the question is less 'what is commonly understood' and more 'what is correct'. A hormone is simply a chemical signal wether between between parts of the body or parts of cells.

It is defined as such both in williams and in Oxford. Each of those covers the various types of hormones before going on to discuss Endrocrine hormones. The reason why the word hormone becomes sensible becomes obvious when considers that cells have a nucleous and organelles that perform specialised functions.

Rather than starting the article with a definition of Endrocrine hormones perhaps it would be better to begin by defining what hormones in general are, staring that there are several types of which Endocrine is the most commoly understood. We can then move on to define the types (and yes I would also regard Neurotrasnmitters and Cytokines as hormones in the Nervous- and Immune- Systems respectivley).

This approach would also allow us to tackle the varied roles of Catechols as both Neurotransmittesr and Endocrine Homrones in one place and make it easy to understand if we keep the level of detail low. E.g. A class of hormones known as Catecholamines have different roles as both Neurotransmitters and Endrocrine Hormones.

This for example is the defitiniton from the Parlex Medical Dictionary 2012.

A chemical substance, formed in one organ or part of the body and carried in the blood to another organ or part where they exert functional effects; depending on the specificity of their effects, hormones can alter the functional activity, and sometimes the structure, of just one organ or tissue or various numbers of them. Various hormones are formed by ductless glands, but molecules such as secretin, cholecystokinin/somatostatin, formed in the gastrointestinal tract, by definition are also hormones. The definition of hormone has been recently extended to chemical substances formed by cells and acting on neighboring cells (that is, paracrine function) or the same cells that produce them (that is, autocrine function). For hormones not listed below, see specific names.

[G. hormōn, pres. part. of hormaō, to rouse or set in motion]

There is also a fifth class of hormone that covers directly adject cells that would be applicable to describe the action of Neurotransmiters. It distingishes itself from Paracarine that affects a number of nearby cells as opposed to adjacent. My copies of Oxford and Williams are both boxed up at present having moved home - should I find them before one of us 'fills in the blank' I will provide a reference.

Leopardtail (talk) 18:30, 5 July 2017 (UTC)


This article needs one or more references to cover the content--FloNight 23:24, 22 November 2005 (UTC)

How Hormones Work[edit]

I'm wondering just how exactly hormones work, this lists what they do, but not how they do it, say a hormone passes by some cells, how does it make/stimulate them to grow, or do whatever it wants them to?

There wasnt much was there? Is the new paragraph better? alteripse 04:26, 9 October 2006 (UTC)

I don't have this information in a Wikipedia friendly format (style & references) but would like to take a stab at answering your question. This information is written in more technical terms on the main page -- I am hoping that the following explanation is easier to follow.

Hormones are chemical substances that while being released in relatively small amounts, travel through the blood stream and cause significant effects. The two major functional categories of hormones are water soluble (amino acid based) and water insoluble (steroids & sterols + thyroxine).

The water soluble hormones will only influence cells that have a receptor protein for that hormone on the surface of their plasma membrane (cell membrane). The receptor is often functionally the first component of a second messenger system which causes a cascade of effects that amplify the signal and ultimately cause many enzymes to be phosphorylated and have their function toggled (on --> off, or off --> on). Paracrines, autocrines, & neurotransmitters can also use second messenger systems but their targets cells are generally very close to the location of where they were released (on the order of millimeters to a maximum of a few centimeters) as they are not released into the blood stream.

Steroid hormones have a very different mechanism of action. They are released from the endocrine gland (adrenal cortex or gonad) and are bound onto a carrier protein that will shuttle hydrophobic substances through the circulatory system. Some steroid hormones have a specific carrier and others use albumin. The lipid soluble steroid hormone can easily dissociate (jump off the carrier protein) and cross the plasma membrane of potential target cells. The steroid hormone will only have an effect if the cell has a receptor in the cytoplasm or nucleoplasm that the steroid can bind onto. If there is a receptor to bind the steroid hormone, the hormone-receptor complex will diffuse into the nucleus and bind onto regions of DNA, altering gene expression.


  • water soluble hormones bind onto a receptor on the surface of the cell and then alter the activity of proteins via a second messenger system.
  • steroid hormones (& thyroxine) bind an intracellular receptor and control the rate of manufacture of proteins at the DNA level.

I hope that helps. If anyone finds the above useful and knows how to convert it into an acceptible format for Wikipedia... ...feel free. Otherwise, I'll try to remember to come back and do it sometime. Dbrouse 23:40, 29 October 2006 (UTC)

removal of estrone and estriol[edit]

I am curious about the removal of my additions (estrone & estriol) to the list of estrogens by Maork. Is there a good reason these should not be listed? Dbrouse 20:07, 29 October 2006 (UTC)

I moved the comment to bottom, where we usually put newer comments and added a heading, as is usual when introducing a new topic. To answer your question, I dont know. I might guess that Maork removed them because they are basically derivatives or less important as human hormones than estradiol, but not really sure. Unfortunately the addition and removal were quickly buried under the vandalism and reversion. I would suggest you could either wait a couple of days and see if Maork responds, replace them in the list and start a conversation if he removes them again without explanation, or put the question on his talk page if he doesnt answer here in a day or two. alteripse 22:06, 29 October 2006 (UTC)

Thank you for the response. I am relatively new to editing in Wikipedia and so I am trying to "learn the ropes." Your personalized response helps remind me that the effort is worth it. Thank you, also, to whoever organinzed this discussion. Dbrouse 23:14, 29 October 2006 (UTC)

After waiting for several months with no response to my question about the deletion, I have added those hormones back. As estriol is necessary for a successful pregnancy, I consider it important and so it should be on the list of Important Human Hormones. Dbrouse

Anger Hormones[edit]

Do they exist? Thanks. UlisesRey 17:48, 10 November 2006 (UTC)

Testosterone has been linked to agressivity. Don't know of any "anger" hormones per se. Horia 19:48, 17 December 2006 (UTC)

Hormone hierarchy.jpeg[edit]

Hormone Hierarchy Image[edit]

Hormone hierarchy.jpeg

This illustration is easy to understand and provides some useful information. I like the general format and style of this image. However, I have some concerns about this illustration: 1) The function of the hormone should probably be included in the illustration. 2) The meaning of the green arrows could be made more clear. In some cases the green arrows are representing control by the nervous system, other times a single arrow represents many controlling hormones, and other times it represents the hormone listed. 3)The target organs listed for thyroxine are simplified to just the liver and muscles. Thyroxine is thought to target all nucleated cells with important function in the heart (influences heart rate) and developing nervous system. Individuals who are deficient in thyroxine in early life develop cretinism. 4) The target organs of vasopressin and oxytocin appear to be reversed. 5) The targets listed for the "sex hormones" testosterone, progesterone, and beta-estradiol are too limited. Although these steroid hormones are considered reproductive hormones, and therefore certainly target the reproductive system, most nucleated cells are targeted by these hormones. 6) I am unsure why the adrenal medulla has been added to this image. The image does not appear to attempt to illustrate all hormones - it's emphasis seems to be just the hypothalamus, pituitary, target organ axis which has a natural hierachy. Why add the adrenal medulla, which is not part of this axis? 7) The endocrine function of the pancreas is NOT primarily regulated by somatotrophin. Insulin and glucagon release is initiated by humoral glucose concentration NOT hormonal stimuli.

It would be nice if images were easy to edit. If so, I would be happy to make these corrections rather than write this note.

Dbrouse 20:24, 17 April 2007 (UTC)

Thanks for drawing attention. I moved the diagram here reluctantly. Someone put a lot of work into it, and it may be salvageable with changes, but there are too many errors to leave it as is. Many of the errors are oversimplifications, since the reality is that most of the hormones affect most of the organ systems of the body, but even the ones that are chosen are sometimes not the primary ones. For example, somatropin (GH) is the most egregious outright error (I suspect the maker meant somatostatin or mixed the two up), as there is no mention of either IGF generation at the liver nor direct effect on skeletal growth, both far better known and more important. The biggest problem is that a top-down "hierarchical" model is so outdated as to be almost quaint-- this is your grandfather's endocrine system, circa 1950. As is illustrated by upside down maps of the world to give fresh perspective, the choice of brain to peripheral organ, like a corporate organization chart, is simply arbitrary and this diagram omits all the hormones that feed back from the periphery to the brain (leptin, inhibin, cytokines, catecholamines etc). From an evolutionary standpoint as well, a chart like this is especially misleading, as even partial "control" by brain is a later developmental characteristic than more diffuse inter-organ signalling. I hate to waste this much work. Anybody have suggestions on how to salvage it? alteripse 08:40, 18 April 2007 (UTC)

I'll never trust my biohemistry textbook again!! I knew this diagram was an over simplification thats why I also wrote elsewhere in the article "However, the hierarchical model is an over simplification of the hormonal signaling process. Typically cellular recipients of a particular hormonal signal may be one of several cell types that reside within a number of different tissues". With regard to the somatropin error or any others I can only apologise on behalf of my textbook, published in 1990, maybe its authors were stuck in the 1950s. I'll certainly be willing to supply my original powerpoint file to anyone who has the necessary expertise and time to improve this diagram. K.murphy 15:02, 20 April 2007 (UTC)

I think we're dealing with a difficult topic here. I think to illustrate the ideas there should be one hormone axis' structure. I suggest the HPThyroid axis as it is least interrupted by other hormones and has trophic hormones which don't share cells with other trophic hormones (like acth or the gonadotrophes... okay another 5am night.. bed time..Markjohndaley 19:02, 14 June 2007 (UTC)

Non-hierarchical hormones[edit]

aren't some hormones secreted independently? Hormona paratiroidea seems like an example of this. Perhaps this should be mentioned. 14:23, 7 May 2007 (UTC)

You are right, and I will change section. PS, around here we call it PTH. alteripse 15:49, 7 May 2007 (UTC)

WikiProject class rating[edit]

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 16:27, 10 November 2007 (UTC)

history of[edit]

I would like to know more about how humanity has discovered hormones. When did we figure out they existed and that they mattered? —Preceding unsigned comment added by (talk) 02:48, 7 February 2008 (UTC)


Minor point but orexin is not a hunger hormone, nor is PYY which is a satiety hormone. Only Ghrelin is a 'hunger hormone'. Satiety hormones include pyy, glp-1 and cck. —Preceding unsigned comment added by (talk) 15:37, 2 April 2008 (UTC)

Missing Hormone?[edit]

I've heard there is a hormone that slows down time in the perception of a human, by increasing the rate at which senses are processed(Or something similar). Could someone lead me to this? Silverfireshadow (talk) 23:30, 11 April 2008 (UTC)

-- (talk) 18:26, 9 September 2008 (UTC)Bold text

Types of hormones[edit]

The chemical classese of hormone described on this page are at odds with the textbook definitions of the classes of hormones. They are normally decribed as being 1) Tyrosine derived, 2) Protein and peptide hormones and 3) Steroid hormones. Is there a reason for the different three classes described in the article? If not, they should be altered to the ones I have just listed. —Preceding unsigned comment added by (talk) 22:09, 7 January 2009 (UTC)

Also it says there are three mayor classes but then there are 4 listed.... — Preceding unsigned comment added by (talk) 19:36, 17 June 2015 (UTC)

New Page for "Important human hormones"[edit]

I think the "Important human hormones" section is just a list and should be moved to its own page. Temporal User (Talk) 05:56, 10 March 2009 (UTC)

Agreed. I'll move it. Fuzzform (talk) 19:53, 25 March 2009 (UTC)

Animal hormones that do NOT travel through the bloodstream?[edit]

This article says "Hormones in animals are often transported in the blood." My understanding is that hormones travel through the bloodstream by definition. Are there examples of hormones that do not travel through the bloodstream?

Thanks... —Preceding unsigned comment added by (talk) 22:23, 4 January 2010 (UTC)

Yes, any hormones in animals that lack blood (jellyfish, flatworms, etc). M. A. Bruhn (talk) 18:18, 30 June 2016 (UTC)

What about Hormones in plants?[edit]

I feel this article is not complete unless it gives information on plant Hormones. Somebody should give that information to complete the artcle. Pathare Prabhu (talk) 12:45, 31 October 2013 (UTC)

Hi Pathare Prabhu! Please, find some good and reliable sources, be bold and add to the article! Lova Falk talk 10:41, 12 November 2013 (UTC)

Hormone replicators and inhibitors[edit]

Not a single word or reference to the environmental toxic effect of hormone replicators and hormone inhibitors in synthetic and industrial produced chemical pollutants? How come? Zero knowledge on it? — Preceding unsigned comment added by 2A02:FE0:C200:1:655E:E248:CA8E:34D9 (talk) 12:20, 16 August 2015 (UTC)

We already have a very extensive article on Endocrine disruptors. Boghog (talk) 12:29, 16 August 2015 (UTC)

Assessment comment[edit]

The comment(s) below were originally left at Talk:Hormone/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

rated top as high school/SAT biology content - tameeria 14:39, 17 February 2007 (UTC) This article has no references. Also, chemical messenger redirects here, which is not entirely correct as chemical messengers can be different from hormones (e.g. second messengers, pheromones). - tameeria 18:23, 18 February 2007 (UTC)

Last edited at 18:23, 18 February 2007 (UTC). Substituted at 18:15, 29 April 2016 (UTC)

This article needs a mention of antagonistic hormones.[edit]

(And I am not the one to do it. BillyBuggy (talk) 07:12, 6 April 2017 (UTC))

Clarify what you mean please. Ideally with an example.--Leopardtail (talk) 18:48, 5 July 2017 (UTC)