ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Clinical Significance And Health Importance On The Actions Of Adrenocorticotropic Hormone (ACTH) On The Adrenal Cortex

Updated on February 11, 2014

ACTH Actions


A General Overview

The secretion of cortisol occurs only in response to stimulation by ACTH. In health, the levels of cortisol are highest in the morning. Adrenocorticotrophic hormone is reciprocally influenced by plasma levels of cortisol, higher levels inhibit and lower levels stimulate production. It (ACTH) also stimulates the melanocytes and activates tissue lipase. The basic actions of ACTH are as follows:

  1. Stimulation and maintenance of growth of the adrenal cortex
  2. Activation of adenylcyclase
  3. Accumulation of cholesterol
  4. Conversion of cholesterol to pregnolone and further steroids.

Actions Of The ACTH

Pituitary rhythm: Within 2-3 hours of falling asleep, the ACTH levels progressively rise and reach its highest level about an hour or so before waking up. During waking ACTH, levels progressively fall to reach the minimum before falling asleep. The secretion of ACTH and cortisol is increased in response to different stress factors such as trauma, fever, surgery, hypoglycemia, severe anxiety and several others. The circadian rhythm disappears during periods of stress and in adrenal tumours.

About 75% of cortisol circulates in blood bound to transcortin which is a glycoprotein, 15% is lossely bound to albumin and 10% circulates in the free state unbound, and the latter accounts for the metabolic activities of the hormone. When plasma cortisol level is high (e.g. Cushing’s syndrome), plasma transcortin is saturated and the level is unbound cortisol increases. This appears in excessive amounts in urine.

Steroid hormones are inactivated mainly in the liver. Other tissues such as muscles, skin, fibroblasts, intestine and lymphocytes also metabolise them.

Adrenal cortical Hormones: Based on their main functional activity, they can be grouped as glucorcorticoids, mineralocorticoids, and sex hormones (androgens and estrogens). Glucocorticoids are secreted by zona fasciculate, mineralocroticoids are produced by zona glomerulosa and sex hormones are produced by zona reticularis.

Glucocorticoids: The important members of this groups are cortisol (hydrocortisone), corticosterone and 11-dehydrocorticosterone. Normal cortisol level at 9 a.m is 140- 700 nmols/liter (5- 25 ug/dl) and it falls to 0.7ug/liter at midnight.

Glucorcoticoids promote gluconeogenesis and lead to hyperglycemia. Other major effects include increase of protein catabolism, suppression of ACTH, anti-inflammatory and anti-allergic action, immunosuppression and reduction in the size of circulating lymphocyte pool and lymphatic organs (lympholysis). In addition, glucocorticoids exert minor effects such as induction of several enzymes, stimulation of hematopoiesis, fat deposition over the trunk, uricosuria, elimination of a water load, production of a feeling of well- being, reduction in circulating eosinophils and maintenance of the capacity for muscular work. Glucocorticoids are used therapeutically for replacement therapy and in many other conditions. Several synthetic analogues are available for therapeutic use.

Mineralocorticoids: Aldosterone is the most important member in this group, the other comparison of the actions of natural and synthetic corticosteroids.

Glucocorticoid activity
Mineralocorticoid activity
Cortisol (hydrocortisone)
Dexamethasone, Betamethasone

The Adrenal Gland


Beign deoxycorticosterone (DOC), these exert their main action on epithelial membranes of the skin, gastrointestinal tract and Kidney. The main action is conservation of sodium and chloride and elimination of potassium. Excessive activity of these hormones cause retention of sodium and chloride, edema and potassium loss. Aldosterone secretion is stimulated by the rennin angiotensin system. ACTH does not exert any appreciable effect on the secretion of aldosterone.

Renin angiotension system: Renin is stored in the form of granules mainly in the modified cells of the afferent arterioles of the glomeruli. Stimuli such as depletion of extracellular volume, reduction of perfusing pressure of the renal artery, stimulation of sympathetic nerves, and rise in sodium concentration at the macula densa lead to release of rennin. It acts on angiotensinogen to covnert it into angiotension I. Angiotension converting enzyme present in the lungs converts angiotensin I to angiotensin II. Actions of angiotension II include secretion of aldosterone, vascoconstriction, and inhibition of rennin secretion.

Sex hormones: Adrenal cortex secretes sex steroids (both androgens and estrogens) which are small in amount compared to the secretion of the gonads. Under normal conditions, they play only a minor role in the development of secondary sex characters. When the secretion is increased under pathological conditions, they may produce virilisation and less commonly feminization which is more obvious in the male. Adrenal estrogen may lead to gynecomastia in males and precocious puberty in girls. In adult women, excessive secretion of adrenal estrogens leads to amenorrhea and infertility. Secretion of sex hormones is under the control of ACTH.

© 2014 Funom Theophilus Makama


    0 of 8192 characters used
    Post Comment

    No comments yet.


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

    Show Details
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)