{"id":4929,"date":"2015-10-28T15:56:05","date_gmt":"2015-10-28T15:56:05","guid":{"rendered":"https:\/\/opentextbc.ca\/biology\/chapter\/18-1-types-of-hormones\/"},"modified":"2021-03-04T00:07:57","modified_gmt":"2021-03-04T00:07:57","slug":"18-1-types-of-hormones","status":"publish","type":"chapter","link":"https:\/\/opentextbc.ca\/biology\/chapter\/18-1-types-of-hormones\/","title":{"raw":"18.1\u00a0Types of Hormones","rendered":"18.1\u00a0Types of Hormones"},"content":{"raw":"<div class=\"titlepage\">\n<div class=\"abstract\">\n<div class=\"bcc-box bcc-highlight\">\n<h3>Learning Objectives<\/h3>\nBy the end of this section, you will be able to:\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n \t<li class=\"listitem\">List the different types of hormones<\/li>\n \t<li class=\"listitem\">Explain their role in maintaining homeostasis<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<span id=\"m44766-fs-idp218838624\"> <\/span>Maintaining homeostasis within the body requires the coordination of many different systems and organs. Communication between neighboring cells, and between cells and tissues in distant parts of the body, occurs through the release of chemicals called hormones. Hormones are released into body fluids (usually blood) that carry these chemicals to their target cells. At the target cells, which are cells that have a receptor for a signal or ligand from a signal cell, the hormones elicit a response. The cells, tissues, and organs that secrete hormones make up the endocrine system. Examples of glands of the endocrine system include the adrenal glands, which produce hormones such as epinephrine and norepinephrine that regulate responses to stress, and the thyroid gland, which produces thyroid hormones that regulate metabolic rates.\n\n<span id=\"m44766-fs-idp213417824\"> <\/span>Although there are many different hormones in the human body, they can be divided into three classes based on their chemical structure: lipid-derived, amino acid-derived, and peptide (peptide and proteins) hormones. One of the key distinguishing features of lipid-derived hormones is that they can diffuse across plasma membranes whereas the amino acid-derived and peptide hormones cannot.\n<div class=\"section\" title=\"Lipid-Derived Hormones (or Lipid-soluble Hormones)\">\n<div class=\"titlepage\">\n<div>\n<div>\n<h2 id=\"m44766-fs-idp127604400\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Lipid-Derived Hormones (or Lipid-soluble Hormones)<\/span><\/span><\/h2>\n<\/div>\n<\/div>\n<\/div>\n<span id=\"m44766-fs-idp278651712\"> <\/span>Most <span id=\"m44766-autoid-cnx2dbk-id1834521\"> <\/span><strong>lipid hormones<\/strong> are derived from cholesterol and thus are structurally similar to it, as illustrated in <a class=\"xref target-figure\" title=\"Figure\u00a037.2.\u00a0\" href=\"#attachment_1217\">Figure 18.2<\/a>. The primary class of lipid hormones in humans is the steroid hormones. Chemically, these hormones are usually ketones or alcohols; their chemical names will end in \u201c-ol\u201d for alcohols or \u201c-one\u201d for ketones. Examples of steroid hormones include estradiol, which is an <span id=\"m44766-autoid-cnx2dbk-id1834535\"> <\/span><strong>estrogen<\/strong>, or female sex hormone, and testosterone, which is an androgen, or male sex hormone. These two hormones are released by the female and male reproductive organs, respectively. Other steroid hormones include aldosterone and cortisol, which are released by the adrenal glands along with some other types of androgens. Steroid hormones are insoluble in water, and they are transported by transport proteins in blood. As a result, they remain in circulation longer than peptide hormones. For example, cortisol has a half-life of 60 to 90 minutes, while epinephrine, an amino acid derived-hormone, has a half-life of approximately one minute.\n\n[caption id=\"attachment_1217\" align=\"aligncenter\" width=\"500\"]<a href=\"http:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2015\/03\/Figure_37_01_01abc.jpg\"><img class=\"wp-image-4926\" src=\"https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/02\/Figure_37_01_01abc.jpg\" alt=\"Figure_37_01_01abc\" width=\"500\" height=\"387\"><\/a> Figure 18.2.\u00a0 The structures shown here represent (a) cholesterol, plus the steroid hormones (b) testosterone and (c) estradiol.[\/caption]\n\n<div class=\"section\" title=\"Amino Acid-Derived Hormones\">\n<div class=\"titlepage\">\n<div>\n<div>\n<h2 id=\"m44766-fs-idm49172336\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Amino Acid-Derived Hormones<\/span><\/span><\/h2>\n<\/div>\n<\/div>\n<\/div>\n<span id=\"m44766-fs-idp229009568\"> <\/span>The <span id=\"m44766-autoid-cnx2dbk-id1827628\"> <\/span><strong>amino acid-derived hormones <\/strong>are relatively small molecules that are derived from the amino acids tyrosine and tryptophan, shown in <a class=\"xref target-figure\" title=\"Figure\u00a037.3.\u00a0\" href=\"#attachment_1218\">Figure 18.3<\/a>. If a hormone is amino acid-derived, its chemical name will end in \u201c-ine\u201d. Examples of amino acid-derived hormones include epinephrine and norepinephrine, which are synthesized in the medulla of the adrenal glands, and thyroxine, which is produced by the thyroid gland. The pineal gland in the brain makes and secretes melatonin which regulates sleep cycles.\n\n[caption id=\"attachment_1218\" align=\"aligncenter\" width=\"500\"]<a href=\"http:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2015\/03\/Figure_37_01_02ab.jpg\"><img class=\"wp-image-4927\" src=\"https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_02ab.jpg\" alt=\"Figure_37_01_02ab\" width=\"500\" height=\"409\"><\/a> Figure 18.3.\u00a0 (a) The hormone epinephrine, which triggers the fight-or-flight response, is derived from the amino acid tyrosine. (b) The hormone melatonin, which regulates circadian rhythms, is derived from the amino acid tryptophan.[\/caption]\n\n<div class=\"section\" title=\"Peptide Hormones\">\n<div class=\"titlepage\">\n<div>\n<div>\n<h2 id=\"m44766-fs-idp209141952\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Peptide Hormones<\/span><\/span><\/h2>\n<\/div>\n<\/div>\n<\/div>\n<span id=\"m44766-fs-idp53021152\"> <\/span>The structure of <span id=\"m44766-autoid-cnx2dbk-id1822953\"> <\/span><strong>peptide hormones<\/strong> is that of a polypeptide chain (chain of amino acids). The peptide hormones include molecules that are short polypeptide chains, such as antidiuretic hormone and oxytocin produced in the brain and released into the blood in the posterior pituitary gland. This class also includes small proteins, like growth hormones produced by the pituitary, and large glycoproteins such as follicle-stimulating hormone produced by the pituitary. <a class=\"xref target-figure\" title=\"Figure\u00a037.4.\u00a0\" href=\"#attachment_1219\">Figure 18.4<\/a> illustrates these peptide hormones.\n\n<span id=\"m44766-fs-idm24624192\"> <\/span>Secreted peptides like insulin are stored within vesicles in the cells that synthesize them. They are then released in response to stimuli such as high blood glucose levels in the case of insulin. Amino acid-derived and polypeptide hormones are water-soluble and insoluble in lipids. These hormones cannot pass through plasma membranes of cells; therefore, their receptors are found on the surface of the target cells.\n\n[caption id=\"attachment_1219\" align=\"aligncenter\" width=\"600\"]<a href=\"http:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2015\/03\/Figure_37_01_03abc.jpg\"><img class=\"wp-image-4928\" src=\"https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_03abc-1024x434-1.jpg\" alt=\"Figure_37_01_03abc\" width=\"600\" height=\"254\"><\/a> Figure 18.4.\u00a0 The structures of peptide hormones (a) oxytocin, (b) growth hormone, and (c) follicle-stimulating hormone are shown. These peptide hormones are much larger than those derived from cholesterol or amino acids.[\/caption]\n\n<div id=\"m44766-fig-ch37_01_03\" class=\"figure\" title=\"Figure\u00a037.4.\u00a0\">\n<div class=\"title\"><\/div>\n<div id=\"m44766-fs-idp92714896\" class=\"note career\">\n<div class=\"title\">\n<div class=\"body\">\n<h2 class=\"title\">Endocrinologist<\/h2>\n<p title=\"Endocrinologist\">An endocrinologist is a medical doctor who specializes in treating disorders of the endocrine glands, hormone systems, and glucose and lipid metabolic pathways. An endocrine surgeon specializes in the surgical treatment of endocrine diseases and glands. Some of the diseases that are managed by endocrinologists: disorders of the pancreas (diabetes mellitus), disorders of the pituitary (gigantism, acromegaly, and pituitary dwarfism), disorders of the thyroid gland (goiter and Graves\u2019 disease), and disorders of the adrenal glands (Cushing\u2019s disease and Addison\u2019s disease).<\/p>\n<span id=\"m44766-fs-idp212309904\"> <\/span>Endocrinologists are required to assess patients and diagnose endocrine disorders through extensive use of laboratory tests. Many endocrine diseases are diagnosed using tests that stimulate or suppress endocrine organ functioning. Blood samples are then drawn to determine the effect of stimulating or suppressing an endocrine organ on the production of hormones. For example, to diagnose diabetes mellitus, patients are required to fast for 12 to 24 hours. They are then given a sugary drink, which stimulates the pancreas to produce insulin to decrease blood glucose levels. A blood sample is taken one to two hours after the sugar drink is consumed. If the pancreas is functioning properly, the blood glucose level will be within a normal range. Another example is the A1C test, which can be performed during blood screening. The A1C test measures average blood glucose levels over the past two to three months by examining how well the blood glucose is being managed over a long time.\n\n<span id=\"m44766-fs-idp15296112\"> <\/span>Once a disease has been diagnosed, endocrinologists can prescribe lifestyle changes and\/or medications to treat the disease. Some cases of diabetes mellitus can be managed by exercise, weight loss, and a healthy diet; in other cases, medications may be required to enhance insulin release. If the disease cannot be controlled by these means, the endocrinologist may prescribe insulin injections.\n\n<span id=\"m44766-fs-idp229970096\"> <\/span>In addition to clinical practice, endocrinologists may also be involved in primary research and development activities. For example, ongoing islet transplant research is investigating how healthy pancreas islet cells may be transplanted into diabetic patients. Successful islet transplants may allow patients to stop taking insulin injections.\n\n<\/div>\n<\/div>\n<h2>Summary<\/h2>\nThere are three basic types of hormones: lipid-derived, amino acid-derived, and peptide. Lipid-derived hormones are structurally similar to cholesterol and include steroid hormones such as estradiol and testosterone. Amino acid-derived hormones are relatively small molecules and include the adrenal hormones epinephrine and norepinephrine. Peptide hormones are polypeptide chains or proteins and include the pituitary hormones, antidiuretic hormone (vasopressin), and oxytocin.\n<div class=\"textbox exercises\">\n<h3>Exercises<\/h3>\n<ol>\n \t<li><span id=\"m44766-fs-idp27103808\">A newly discovered hormone contains four amino acids linked together. Under which chemical class would this hormone be classified?<\/span>\n<ol>\n \t<li>libid-derived hormone<\/li>\n \t<li>amino acid-derived hormone<\/li>\n \t<li>peptide hormone<\/li>\n \t<li>glycoprotien<\/li>\n<\/ol>\n<\/li>\n \t<li>Which class of hormones can diffuse through plasma membranes?\n<ol>\n \t<li>libid-derived hormones<\/li>\n \t<li>amino acid-derived hormones<\/li>\n \t<li>peptide hormones<\/li>\n \t<li>glycoprotien hormones<\/li>\n<\/ol>\n<\/li>\n \t<li>Although there are many different hormones in the human body, they can be divided into three classes based on their chemical structure. What are these classes and what is one factor that distinguishes them?<\/li>\n \t<li>Where is insulin stored, and why would it be released?<\/li>\n<\/ol>\n<strong>Answers<\/strong>\n<ol>\n \t<li>C<\/li>\n \t<li>A<\/li>\n \t<li>Although there are many different hormones in the human body, they can be divided into three classes based on their chemical structure: lipid-derived, amino acid-derived, and peptide hormones. One of the key distinguishing features of the lipid-derived hormones is that they can diffuse across plasma membranes whereas the amino acid-derived and peptide hormones cannot.<\/li>\n \t<li>Secreted peptides such as insulin are stored within vesicles in the cells that synthesize them. They are then released in response to stimuli such as high blood glucose levels in the case of insulin.<\/li>\n<\/ol>\n<\/div>\n<div class=\"body\">\n<div id=\"m44768-fs-idp147588368\" class=\"exercise\">\n<div class=\"title\">\n<div class=\"body\">\n<div id=\"m44766-fs-idm4431424\" class=\"exercise\">\n<div class=\"body\">\n<div id=\"m44766-fs-idp278234800\" class=\"solution labeled\"><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"section module\" title=\"37.5.\u00a0Endocrine Glands\" xml:lang=\"en\">\n<div class=\"section\" title=\"Organs with Secondary Endocrine Functions\"><\/div>\n<div id=\"id799791\" class=\"glossary\" title=\"Glossary\">\n<div class=\"titlepage\">\n<div class=\"bcc-box bcc-success\">\n<h3>Glossary<\/h3>\n<dl>\n \t<dt><strong>amino acid-derived hormone<\/strong><\/dt>\n \t<dd>hormone derived from amino acids<\/dd>\n \t<dt><strong>estrogens<\/strong><\/dt>\n \t<dd>- a group of steroid hormones, including estradiol and several others, that are produced by the ovaries and elicit<\/dd>\n \t<dt><strong>lipid-derived hormone<\/strong><\/dt>\n \t<dd>hormone derived mostly from cholesterol<\/dd>\n \t<dt><strong>peptide hormone<\/strong><\/dt>\n \t<dd>hormone composed of a polypeptide chain<\/dd>\n<\/dl>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"cnx-eoc summary\">\n<div class=\"section\"><\/div>\n<\/div>\n<\/div>\n<\/div>","rendered":"<div class=\"titlepage\">\n<div class=\"abstract\">\n<div class=\"bcc-box bcc-highlight\">\n<h3>Learning Objectives<\/h3>\n<p>By the end of this section, you will be able to:<\/p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">List the different types of hormones<\/li>\n<li class=\"listitem\">Explain their role in maintaining homeostasis<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<p><span id=\"m44766-fs-idp218838624\"> <\/span>Maintaining homeostasis within the body requires the coordination of many different systems and organs. Communication between neighboring cells, and between cells and tissues in distant parts of the body, occurs through the release of chemicals called hormones. Hormones are released into body fluids (usually blood) that carry these chemicals to their target cells. At the target cells, which are cells that have a receptor for a signal or ligand from a signal cell, the hormones elicit a response. The cells, tissues, and organs that secrete hormones make up the endocrine system. Examples of glands of the endocrine system include the adrenal glands, which produce hormones such as epinephrine and norepinephrine that regulate responses to stress, and the thyroid gland, which produces thyroid hormones that regulate metabolic rates.<\/p>\n<p><span id=\"m44766-fs-idp213417824\"> <\/span>Although there are many different hormones in the human body, they can be divided into three classes based on their chemical structure: lipid-derived, amino acid-derived, and peptide (peptide and proteins) hormones. One of the key distinguishing features of lipid-derived hormones is that they can diffuse across plasma membranes whereas the amino acid-derived and peptide hormones cannot.<\/p>\n<div class=\"section\" title=\"Lipid-Derived Hormones (or Lipid-soluble Hormones)\">\n<div class=\"titlepage\">\n<div>\n<div>\n<h2 id=\"m44766-fs-idp127604400\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Lipid-Derived Hormones (or Lipid-soluble Hormones)<\/span><\/span><\/h2>\n<\/div>\n<\/div>\n<\/div>\n<p><span id=\"m44766-fs-idp278651712\"> <\/span>Most <span id=\"m44766-autoid-cnx2dbk-id1834521\"> <\/span><strong>lipid hormones<\/strong> are derived from cholesterol and thus are structurally similar to it, as illustrated in <a class=\"xref target-figure\" title=\"Figure\u00a037.2.\u00a0\" href=\"#attachment_1217\">Figure 18.2<\/a>. The primary class of lipid hormones in humans is the steroid hormones. Chemically, these hormones are usually ketones or alcohols; their chemical names will end in \u201c-ol\u201d for alcohols or \u201c-one\u201d for ketones. Examples of steroid hormones include estradiol, which is an <span id=\"m44766-autoid-cnx2dbk-id1834535\"> <\/span><strong>estrogen<\/strong>, or female sex hormone, and testosterone, which is an androgen, or male sex hormone. These two hormones are released by the female and male reproductive organs, respectively. Other steroid hormones include aldosterone and cortisol, which are released by the adrenal glands along with some other types of androgens. Steroid hormones are insoluble in water, and they are transported by transport proteins in blood. As a result, they remain in circulation longer than peptide hormones. For example, cortisol has a half-life of 60 to 90 minutes, while epinephrine, an amino acid derived-hormone, has a half-life of approximately one minute.<\/p>\n<figure id=\"attachment_1217\" aria-describedby=\"caption-attachment-1217\" style=\"width: 500px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2015\/03\/Figure_37_01_01abc.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-4926\" src=\"https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/02\/Figure_37_01_01abc.jpg\" alt=\"Figure_37_01_01abc\" width=\"500\" height=\"387\" srcset=\"https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/02\/Figure_37_01_01abc.jpg 757w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/02\/Figure_37_01_01abc-300x232.jpg 300w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/02\/Figure_37_01_01abc-65x50.jpg 65w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/02\/Figure_37_01_01abc-225x174.jpg 225w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/02\/Figure_37_01_01abc-350x271.jpg 350w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><figcaption id=\"caption-attachment-1217\" class=\"wp-caption-text\">Figure 18.2.\u00a0 The structures shown here represent (a) cholesterol, plus the steroid hormones (b) testosterone and (c) estradiol.<\/figcaption><\/figure>\n<div class=\"section\" title=\"Amino Acid-Derived Hormones\">\n<div class=\"titlepage\">\n<div>\n<div>\n<h2 id=\"m44766-fs-idm49172336\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Amino Acid-Derived Hormones<\/span><\/span><\/h2>\n<\/div>\n<\/div>\n<\/div>\n<p><span id=\"m44766-fs-idp229009568\"> <\/span>The <span id=\"m44766-autoid-cnx2dbk-id1827628\"> <\/span><strong>amino acid-derived hormones <\/strong>are relatively small molecules that are derived from the amino acids tyrosine and tryptophan, shown in <a class=\"xref target-figure\" title=\"Figure\u00a037.3.\u00a0\" href=\"#attachment_1218\">Figure 18.3<\/a>. If a hormone is amino acid-derived, its chemical name will end in \u201c-ine\u201d. Examples of amino acid-derived hormones include epinephrine and norepinephrine, which are synthesized in the medulla of the adrenal glands, and thyroxine, which is produced by the thyroid gland. The pineal gland in the brain makes and secretes melatonin which regulates sleep cycles.<\/p>\n<figure id=\"attachment_1218\" aria-describedby=\"caption-attachment-1218\" style=\"width: 500px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2015\/03\/Figure_37_01_02ab.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-4927\" src=\"https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_02ab.jpg\" alt=\"Figure_37_01_02ab\" width=\"500\" height=\"409\" srcset=\"https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_02ab.jpg 665w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_02ab-300x245.jpg 300w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_02ab-65x53.jpg 65w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_02ab-225x184.jpg 225w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_02ab-350x286.jpg 350w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><figcaption id=\"caption-attachment-1218\" class=\"wp-caption-text\">Figure 18.3.\u00a0 (a) The hormone epinephrine, which triggers the fight-or-flight response, is derived from the amino acid tyrosine. (b) The hormone melatonin, which regulates circadian rhythms, is derived from the amino acid tryptophan.<\/figcaption><\/figure>\n<div class=\"section\" title=\"Peptide Hormones\">\n<div class=\"titlepage\">\n<div>\n<div>\n<h2 id=\"m44766-fs-idp209141952\"><span class=\"cnx-gentext-section cnx-gentext-autogenerated\"><span class=\"cnx-gentext-section cnx-gentext-t\">Peptide Hormones<\/span><\/span><\/h2>\n<\/div>\n<\/div>\n<\/div>\n<p><span id=\"m44766-fs-idp53021152\"> <\/span>The structure of <span id=\"m44766-autoid-cnx2dbk-id1822953\"> <\/span><strong>peptide hormones<\/strong> is that of a polypeptide chain (chain of amino acids). The peptide hormones include molecules that are short polypeptide chains, such as antidiuretic hormone and oxytocin produced in the brain and released into the blood in the posterior pituitary gland. This class also includes small proteins, like growth hormones produced by the pituitary, and large glycoproteins such as follicle-stimulating hormone produced by the pituitary. <a class=\"xref target-figure\" title=\"Figure\u00a037.4.\u00a0\" href=\"#attachment_1219\">Figure 18.4<\/a> illustrates these peptide hormones.<\/p>\n<p><span id=\"m44766-fs-idm24624192\"> <\/span>Secreted peptides like insulin are stored within vesicles in the cells that synthesize them. They are then released in response to stimuli such as high blood glucose levels in the case of insulin. Amino acid-derived and polypeptide hormones are water-soluble and insoluble in lipids. These hormones cannot pass through plasma membranes of cells; therefore, their receptors are found on the surface of the target cells.<\/p>\n<figure id=\"attachment_1219\" aria-describedby=\"caption-attachment-1219\" style=\"width: 600px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2015\/03\/Figure_37_01_03abc.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-4928\" src=\"https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_03abc-1024x434-1.jpg\" alt=\"Figure_37_01_03abc\" width=\"600\" height=\"254\" srcset=\"https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_03abc-1024x434-1.jpg 1024w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_03abc-1024x434-1-300x127.jpg 300w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_03abc-1024x434-1-768x326.jpg 768w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_03abc-1024x434-1-65x28.jpg 65w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_03abc-1024x434-1-225x95.jpg 225w, https:\/\/opentextbc.ca\/biology\/wp-content\/uploads\/sites\/96\/2021\/03\/Figure_37_01_03abc-1024x434-1-350x148.jpg 350w\" sizes=\"auto, (max-width: 600px) 100vw, 600px\" \/><\/a><figcaption id=\"caption-attachment-1219\" class=\"wp-caption-text\">Figure 18.4.\u00a0 The structures of peptide hormones (a) oxytocin, (b) growth hormone, and (c) follicle-stimulating hormone are shown. These peptide hormones are much larger than those derived from cholesterol or amino acids.<\/figcaption><\/figure>\n<div id=\"m44766-fig-ch37_01_03\" class=\"figure\" title=\"Figure\u00a037.4.\u00a0\">\n<div class=\"title\"><\/div>\n<div id=\"m44766-fs-idp92714896\" class=\"note career\">\n<div class=\"title\">\n<div class=\"body\">\n<h2 class=\"title\">Endocrinologist<\/h2>\n<p title=\"Endocrinologist\">An endocrinologist is a medical doctor who specializes in treating disorders of the endocrine glands, hormone systems, and glucose and lipid metabolic pathways. An endocrine surgeon specializes in the surgical treatment of endocrine diseases and glands. Some of the diseases that are managed by endocrinologists: disorders of the pancreas (diabetes mellitus), disorders of the pituitary (gigantism, acromegaly, and pituitary dwarfism), disorders of the thyroid gland (goiter and Graves\u2019 disease), and disorders of the adrenal glands (Cushing\u2019s disease and Addison\u2019s disease).<\/p>\n<p><span id=\"m44766-fs-idp212309904\"> <\/span>Endocrinologists are required to assess patients and diagnose endocrine disorders through extensive use of laboratory tests. Many endocrine diseases are diagnosed using tests that stimulate or suppress endocrine organ functioning. Blood samples are then drawn to determine the effect of stimulating or suppressing an endocrine organ on the production of hormones. For example, to diagnose diabetes mellitus, patients are required to fast for 12 to 24 hours. They are then given a sugary drink, which stimulates the pancreas to produce insulin to decrease blood glucose levels. A blood sample is taken one to two hours after the sugar drink is consumed. If the pancreas is functioning properly, the blood glucose level will be within a normal range. Another example is the A1C test, which can be performed during blood screening. The A1C test measures average blood glucose levels over the past two to three months by examining how well the blood glucose is being managed over a long time.<\/p>\n<p><span id=\"m44766-fs-idp15296112\"> <\/span>Once a disease has been diagnosed, endocrinologists can prescribe lifestyle changes and\/or medications to treat the disease. Some cases of diabetes mellitus can be managed by exercise, weight loss, and a healthy diet; in other cases, medications may be required to enhance insulin release. If the disease cannot be controlled by these means, the endocrinologist may prescribe insulin injections.<\/p>\n<p><span id=\"m44766-fs-idp229970096\"> <\/span>In addition to clinical practice, endocrinologists may also be involved in primary research and development activities. For example, ongoing islet transplant research is investigating how healthy pancreas islet cells may be transplanted into diabetic patients. Successful islet transplants may allow patients to stop taking insulin injections.<\/p>\n<\/div>\n<\/div>\n<h2>Summary<\/h2>\n<p>There are three basic types of hormones: lipid-derived, amino acid-derived, and peptide. Lipid-derived hormones are structurally similar to cholesterol and include steroid hormones such as estradiol and testosterone. Amino acid-derived hormones are relatively small molecules and include the adrenal hormones epinephrine and norepinephrine. Peptide hormones are polypeptide chains or proteins and include the pituitary hormones, antidiuretic hormone (vasopressin), and oxytocin.<\/p>\n<div class=\"textbox exercises\">\n<h3>Exercises<\/h3>\n<ol>\n<li><span id=\"m44766-fs-idp27103808\">A newly discovered hormone contains four amino acids linked together. Under which chemical class would this hormone be classified?<\/span>\n<ol>\n<li>libid-derived hormone<\/li>\n<li>amino acid-derived hormone<\/li>\n<li>peptide hormone<\/li>\n<li>glycoprotien<\/li>\n<\/ol>\n<\/li>\n<li>Which class of hormones can diffuse through plasma membranes?\n<ol>\n<li>libid-derived hormones<\/li>\n<li>amino acid-derived hormones<\/li>\n<li>peptide hormones<\/li>\n<li>glycoprotien hormones<\/li>\n<\/ol>\n<\/li>\n<li>Although there are many different hormones in the human body, they can be divided into three classes based on their chemical structure. What are these classes and what is one factor that distinguishes them?<\/li>\n<li>Where is insulin stored, and why would it be released?<\/li>\n<\/ol>\n<p><strong>Answers<\/strong><\/p>\n<ol>\n<li>C<\/li>\n<li>A<\/li>\n<li>Although there are many different hormones in the human body, they can be divided into three classes based on their chemical structure: lipid-derived, amino acid-derived, and peptide hormones. One of the key distinguishing features of the lipid-derived hormones is that they can diffuse across plasma membranes whereas the amino acid-derived and peptide hormones cannot.<\/li>\n<li>Secreted peptides such as insulin are stored within vesicles in the cells that synthesize them. They are then released in response to stimuli such as high blood glucose levels in the case of insulin.<\/li>\n<\/ol>\n<\/div>\n<div class=\"body\">\n<div id=\"m44768-fs-idp147588368\" class=\"exercise\">\n<div class=\"title\">\n<div class=\"body\">\n<div id=\"m44766-fs-idm4431424\" class=\"exercise\">\n<div class=\"body\">\n<div id=\"m44766-fs-idp278234800\" class=\"solution labeled\"><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"section module\" title=\"37.5.\u00a0Endocrine Glands\" xml:lang=\"en\">\n<div class=\"section\" title=\"Organs with Secondary Endocrine Functions\"><\/div>\n<div id=\"id799791\" class=\"glossary\" title=\"Glossary\">\n<div class=\"titlepage\">\n<div class=\"bcc-box bcc-success\">\n<h3>Glossary<\/h3>\n<dl>\n<dt><strong>amino acid-derived hormone<\/strong><\/dt>\n<dd>hormone derived from amino acids<\/dd>\n<dt><strong>estrogens<\/strong><\/dt>\n<dd>&#8211; a group of steroid hormones, including estradiol and several others, that are produced by the ovaries and elicit<\/dd>\n<dt><strong>lipid-derived hormone<\/strong><\/dt>\n<dd>hormone derived mostly from cholesterol<\/dd>\n<dt><strong>peptide hormone<\/strong><\/dt>\n<dd>hormone composed of a polypeptide chain<\/dd>\n<\/dl>\n<\/div>\n<\/div>\n<\/div>\n<div class=\"cnx-eoc summary\">\n<div class=\"section\"><\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"author":90,"menu_order":39,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":"cc-by"},"chapter-type":[],"contributor":[],"license":[57],"class_list":["post-4929","chapter","type-chapter","status-publish","hentry","license-cc-by"],"part":4924,"_links":{"self":[{"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/pressbooks\/v2\/chapters\/4929","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/wp\/v2\/users\/90"}],"version-history":[{"count":1,"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/pressbooks\/v2\/chapters\/4929\/revisions"}],"predecessor-version":[{"id":4930,"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/pressbooks\/v2\/chapters\/4929\/revisions\/4930"}],"part":[{"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/pressbooks\/v2\/parts\/4924"}],"metadata":[{"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/pressbooks\/v2\/chapters\/4929\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/wp\/v2\/media?parent=4929"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/pressbooks\/v2\/chapter-type?post=4929"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/wp\/v2\/contributor?post=4929"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/opentextbc.ca\/biology\/wp-json\/wp\/v2\/license?post=4929"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}